Esc alternates between the last two panes; Toggleterm is gone

Esc ran Toggleterm, which hopped between the newest DOC and the newest
TERMINAL. That distinction never earned its keep. It made Esc unpredictable —
which of three panes you landed on depended on their kinds, not on where you
had been — and it could not alternate between two files at all, which is the
case you hit most. Editing two files, Esc did nothing.

The replacement already existed. Last (SPC j j) is "the pane you were in
before this one, whichever it was": it walks the jump stack for the newest
entry naming a different pane and restores its line and column. So Esc, and
Shift-Esc in tty, now run Last, and Toggleterm is deleted rather than renamed
— a third implementation of "go to the other pane" was the thing to avoid.
SPC w t goes with it; the w group is the four directional moves, and the jump
group already had SPC j j.

Held down, Esc alternates. Two files, a file and its shell, a file and a
+Search — all the same, because Last has no notion of kind to get wrong.

This depends on the swap in the same series: Last reads the stack backwards,
and until hopping stopped appending, the pane you came from could fall off it.

windownav.snap needed only its keys and prose changed — its golden did not
move at all, which is the useful evidence here: for the one scenario the old
builtin handled well, Last produces an identical focus sequence.

Coverage for what it did not handle is new: a unit test opens a second FILE by
looking its name and asserts Esc alternates between two panes of the SAME
kind, which is the case that used to be a no-op.

Docs follow: tutor.txt, docs/helix-keys.md, docs/design.typ, and the builtin
index goldens, which are now one row shorter.

75/75 snapshots, both unit suites, and the macOS ABI build all pass.

1 files changed, 27 insertions, 27 deletions

diff --git a/test/snapshots/themesel.golden b/test/snapshots/themesel.golden
index 2f2568ec..08d5a271 100644
--- a/test/snapshots/themesel.golden
+++ b/test/snapshots/themesel.golden
@@ -1,6 +1,6 @@
 == snap boot grid=100x30 cursor=7,2
 |New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
-|  /tmp/pardes-snap/themesel/cwd/t.txt Save New Del
+|  /tmp/pardes-snap/themesel/cwd/t.txt                               Save New Del
 |     1 line 1
 |     2 line 2
 |     3 line 3
@@ -31,7 +31,7 @@
 |    28 line 28
 == snap list grid=100x30 cursor=7,2
 |New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
-|  /tmp/pardes-snap/themesel/cwd/t.txt Save New Del
+|  /tmp/pardes-snap/themesel/cwd/t.txt                               Save New Del
 |     1 line 1
 |     2 line 2
 |     3 line 3
@@ -46,7 +46,7 @@
 |    12 line 12
 |    13 line 13
 |    14 line 14
-|  /tmp/pardes-snap/themesel/cwd/+Themes New Del
+|  /tmp/pardes-snap/themesel/cwd/+Themes                                  New Del
 |     1 Theme helix
 |     2 Theme dark
 |     3 Theme acme
@@ -62,7 +62,7 @@
 |    13 Theme ashen
 == snap step-helix grid=100x30 cursor=7,2
 |New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
-|  /tmp/pardes-snap/themesel/cwd/t.txt Save New Del
+|  /tmp/pardes-snap/themesel/cwd/t.txt                               Save New Del
 |     1 line 1
 |     2 line 2
 |     3 line 3
@@ -77,7 +77,7 @@
 |    12 line 12
 |    13 line 13
 |    14 line 14
-|  /tmp/pardes-snap/themesel/cwd/+Themes New Del
+|  /tmp/pardes-snap/themesel/cwd/+Themes                                  New Del
 |     1 Theme helix
 |     2 Theme dark
 |     3 Theme acme
@@ -93,7 +93,7 @@
 |    13 Theme ashen
 == style step-helix
 |0: 0-56 #949494,#121212, 57-99 d,#121212,
-|1: 0-1 #ffffff,#626262, 2-49 #949494,#121212, 50-99 d,#121212,
+|1: 0-1 #ffffff,#626262, 2-79 #949494,#121212, 80-99 d,#121212,
 |2: 0-0 d,#444444, 1-1 d,#080808, 2-6 #949494,#121212, 7-12 #bdbdbd,#080808, 13-99 d,#080808,
 |3: 0-0 d,#444444, 1-1 d,#080808, 2-6 #626262,#080808, 7-12 #bdbdbd,#080808, 13-99 d,#080808,
 |4: 0-0 d,#444444, 1-1 d,#080808, 2-6 #626262,#080808, 7-12 #bdbdbd,#080808, 13-99 d,#080808,
@@ -108,7 +108,7 @@
 |13: 0-0 d,#121212, 1-1 d,#080808, 2-6 #626262,#080808, 7-13 #bdbdbd,#080808, 14-99 d,#080808,
 |14: 0-0 d,#121212, 1-1 d,#080808, 2-6 #626262,#080808, 7-13 #bdbdbd,#080808, 14-99 d,#080808,
 |15: 0-0 d,#121212, 1-1 d,#080808, 2-6 #626262,#080808, 7-13 #bdbdbd,#080808, 14-99 d,#080808,
-|16: 0-1 #ffffff,#262626, 2-46 #949494,#121212, 47-99 d,#121212,
+|16: 0-1 #ffffff,#262626, 2-79 #949494,#121212, 80-99 d,#121212,
 |17: 0-0 d,#444444, 1-1 d,#080808, 2-6 #626262,#080808, 7-99 #080808,#80a0ff,
 |18: 0-0 d,#121212, 1-1 d,#080808, 2-6 #626262,#080808, 7-16 #bdbdbd,#080808, 17-99 d,#080808,
 |19: 0-0 d,#121212, 1-1 d,#080808, 2-6 #626262,#080808, 7-16 #bdbdbd,#080808, 17-99 d,#080808,
@@ -124,7 +124,7 @@
 |29: 0-0 d,#121212, 1-1 d,#080808, 2-6 #626262,#080808, 7-17 #bdbdbd,#080808, 18-99 d,#080808,
 == snap step-dark grid=100x30 cursor=7,2
 |New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
-|  /tmp/pardes-snap/themesel/cwd/t.txt Save New Del
+|  /tmp/pardes-snap/themesel/cwd/t.txt                               Save New Del
 |     1 line 1
 |     2 line 2
 |     3 line 3
@@ -139,7 +139,7 @@
 |    12 line 12
 |    13 line 13
 |    14 line 14
-|  /tmp/pardes-snap/themesel/cwd/+Themes New Del
+|  /tmp/pardes-snap/themesel/cwd/+Themes                                  New Del
 |     1 Theme helix
 |     2 Theme dark
 |     3 Theme acme
@@ -155,7 +155,7 @@
 |    13 Theme ashen
 == style step-dark
 |0: 0-56 #969696,#2c2a3e, 57-99 d,#2c2a3e,
-|1: 0-1 #ffffff,#6e4fd0, 2-49 #969696,#2c2a3e, 50-99 d,#2c2a3e,
+|1: 0-1 #ffffff,#6e4fd0, 2-79 #969696,#2c2a3e, 80-99 d,#2c2a3e,
 |2: 0-0 d,#525252, 1-1 d,d, 2-6 #969696,#2c2a3e, 7-99 d,d,
 |3: 0-0 d,#525252, 1-1 d,d, 2-6 #5a5a5a,d, 7-99 d,d,
 |4: 0-0 d,#525252, 1-1 d,d, 2-6 #5a5a5a,d, 7-99 d,d,
@@ -170,7 +170,7 @@
 |13: 0-0 d,#2a2a2a, 1-1 d,d, 2-6 #5a5a5a,d, 7-99 d,d,
 |14: 0-0 d,#2a2a2a, 1-1 d,d, 2-6 #5a5a5a,d, 7-99 d,d,
 |15: 0-0 d,#2a2a2a, 1-1 d,d, 2-6 #5a5a5a,d, 7-99 d,d,
-|16: 0-1 #ffffff,#383c54, 2-46 #969696,#2c2a3e, 47-99 d,#2c2a3e,
+|16: 0-1 #ffffff,#383c54, 2-79 #969696,#2c2a3e, 80-99 d,#2c2a3e,
 |17: 0-0 d,#525252, 1-1 d,d, 2-6 #5a5a5a,d, 7-99 d,d,
 |18: 0-0 d,#2a2a2a, 1-1 d,d, 2-6 #5a5a5a,d, 7-99 #d8c8a8,#4a3a1e,
 |19: 0-0 d,#2a2a2a, 1-1 d,d, 2-6 #5a5a5a,d, 7-99 d,d,
@@ -186,7 +186,7 @@
 |29: 0-0 d,#2a2a2a, 1-1 d,d, 2-6 #5a5a5a,d, 7-99 d,d,
 == snap step-acme grid=100x30 cursor=7,2
 |New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
-|  /tmp/pardes-snap/themesel/cwd/t.txt Save New Del
+|  /tmp/pardes-snap/themesel/cwd/t.txt                               Save New Del
 |     1 line 1
 |     2 line 2
 |     3 line 3
@@ -201,7 +201,7 @@
 |    12 line 12
 |    13 line 13
 |    14 line 14
-|  /tmp/pardes-snap/themesel/cwd/+Themes New Del
+|  /tmp/pardes-snap/themesel/cwd/+Themes                                  New Del
 |     1 Theme helix
 |     2 Theme dark
 |     3 Theme acme
@@ -217,7 +217,7 @@
 |    13 Theme ashen
 == style step-acme
 |0: 0-56 #000000,#eaffff, 57-99 d,#eaffff,
-|1: 0-1 #ffffff,#6e4fd0, 2-49 #000000,#eaffff, 50-99 d,#eaffff,
+|1: 0-1 #ffffff,#6e4fd0, 2-79 #000000,#eaffff, 80-99 d,#eaffff,
 |2: 0-1 d,#ffffea, 2-6 #000000,#eaffff, 7-12 #000000,#ffffea, 13-99 d,#ffffea,
 |3: 0-1 d,#ffffea, 2-6 #999980,#ffffea, 7-12 #000000,#ffffea, 13-99 d,#ffffea,
 |4: 0-1 d,#ffffea, 2-6 #999980,#ffffea, 7-12 #000000,#ffffea, 13-99 d,#ffffea,
@@ -232,7 +232,7 @@
 |13: 0-0 d,#99994c, 1-1 d,#ffffea, 2-6 #999980,#ffffea, 7-13 #000000,#ffffea, 14-99 d,#ffffea,
 |14: 0-0 d,#99994c, 1-1 d,#ffffea, 2-6 #999980,#ffffea, 7-13 #000000,#ffffea, 14-99 d,#ffffea,
 |15: 0-0 d,#99994c, 1-1 d,#ffffea, 2-6 #999980,#ffffea, 7-13 #000000,#ffffea, 14-99 d,#ffffea,
-|16: 0-1 #ffffff,#383c54, 2-46 #000000,#eaffff, 47-99 d,#eaffff,
+|16: 0-1 #ffffff,#383c54, 2-79 #000000,#eaffff, 80-99 d,#eaffff,
 |17: 0-1 d,#ffffea, 2-6 #999980,#ffffea, 7-17 #000000,#ffffea, 18-99 d,#ffffea,
 |18: 0-0 d,#99994c, 1-1 d,#ffffea, 2-6 #999980,#ffffea, 7-16 #000000,#ffffea, 17-99 d,#ffffea,
 |19: 0-0 d,#99994c, 1-1 d,#ffffea, 2-6 #999980,#ffffea, 7-99 #000000,#eeee9e,
@@ -248,7 +248,7 @@
 |29: 0-0 d,#99994c, 1-1 d,#ffffea, 2-6 #999980,#ffffea, 7-17 #000000,#ffffea, 18-99 d,#ffffea,
 == snap step-generated grid=100x30 cursor=7,2
 |New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
-|  /tmp/pardes-snap/themesel/cwd/t.txt Save New Del
+|  /tmp/pardes-snap/themesel/cwd/t.txt                               Save New Del
 |     1 line 1
 |     2 line 2
 |     3 line 3
@@ -263,7 +263,7 @@
 |    12 line 12
 |    13 line 13
 |    14 line 14
-|  /tmp/pardes-snap/themesel/cwd/+Themes New Del
+|  /tmp/pardes-snap/themesel/cwd/+Themes                                  New Del
 |     1 Theme helix
 |     2 Theme dark
 |     3 Theme acme
@@ -279,7 +279,7 @@
 |    13 Theme ashen
 == style step-generated
 |0: 0-56 #e0e0e0,#1e262e, 57-99 d,#1e262e,
-|1: 0-1 #000000,#ffa060, 2-49 #e0e0e0,#1e262e, 50-99 d,#1e262e,
+|1: 0-1 #000000,#ffa060, 2-79 #e0e0e0,#1e262e, 80-99 d,#1e262e,
 |2: 0-0 d,#303840, 1-1 d,#161e26, 2-6 #e0e0e0,#1e262e, 7-12 #e0e0e0,#161e26, 13-99 d,#161e26,
 |3: 0-0 d,#303840, 1-1 d,#161e26, 2-6 #303840,#161e26, 7-12 #e0e0e0,#161e26, 13-99 d,#161e26,
 |4: 0-0 d,#303840, 1-1 d,#161e26, 2-6 #303840,#161e26, 7-12 #e0e0e0,#161e26, 13-99 d,#161e26,
@@ -294,7 +294,7 @@
 |13: 0-0 d,#1e262e, 1-1 d,#161e26, 2-6 #303840,#161e26, 7-13 #e0e0e0,#161e26, 14-99 d,#161e26,
 |14: 0-0 d,#1e262e, 1-1 d,#161e26, 2-6 #303840,#161e26, 7-13 #e0e0e0,#161e26, 14-99 d,#161e26,
 |15: 0-0 d,#1e262e, 1-1 d,#161e26, 2-6 #303840,#161e26, 7-13 #e0e0e0,#161e26, 14-99 d,#161e26,
-|16: 0-1 #ffffff,#303840, 2-46 #e0e0e0,#1e262e, 47-99 d,#1e262e,
+|16: 0-1 #ffffff,#303840, 2-79 #e0e0e0,#1e262e, 80-99 d,#1e262e,
 |17: 0-0 d,#303840, 1-1 d,#161e26, 2-6 #303840,#161e26, 7-17 #e0e0e0,#161e26, 18-99 d,#161e26,
 |18: 0-0 d,#1e262e, 1-1 d,#161e26, 2-6 #303840,#161e26, 7-16 #e0e0e0,#161e26, 17-99 d,#161e26,
 |19: 0-0 d,#1e262e, 1-1 d,#161e26, 2-6 #303840,#161e26, 7-16 #e0e0e0,#161e26, 17-99 d,#161e26,
@@ -310,7 +310,7 @@
 |29: 0-0 d,#1e262e, 1-1 d,#161e26, 2-6 #303840,#161e26, 7-17 #e0e0e0,#161e26, 18-99 d,#161e26,
 == snap step-back grid=100x30 cursor=7,2
 |New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
-|  /tmp/pardes-snap/themesel/cwd/t.txt Save New Del
+|  /tmp/pardes-snap/themesel/cwd/t.txt                               Save New Del
 |     1 line 1
 |     2 line 2
 |     3 line 3
@@ -325,7 +325,7 @@
 |    12 line 12
 |    13 line 13
 |    14 line 14
-|  /tmp/pardes-snap/themesel/cwd/+Themes New Del
+|  /tmp/pardes-snap/themesel/cwd/+Themes                                  New Del
 |     1 Theme helix
 |     2 Theme dark
 |     3 Theme acme
@@ -341,7 +341,7 @@
 |    13 Theme ashen
 == style step-back
 |0: 0-56 #000000,#eaffff, 57-99 d,#eaffff,
-|1: 0-1 #ffffff,#6e4fd0, 2-49 #000000,#eaffff, 50-99 d,#eaffff,
+|1: 0-1 #ffffff,#6e4fd0, 2-79 #000000,#eaffff, 80-99 d,#eaffff,
 |2: 0-1 d,#ffffea, 2-6 #000000,#eaffff, 7-12 #000000,#ffffea, 13-99 d,#ffffea,
 |3: 0-1 d,#ffffea, 2-6 #999980,#ffffea, 7-12 #000000,#ffffea, 13-99 d,#ffffea,
 |4: 0-1 d,#ffffea, 2-6 #999980,#ffffea, 7-12 #000000,#ffffea, 13-99 d,#ffffea,
@@ -356,7 +356,7 @@
 |13: 0-0 d,#99994c, 1-1 d,#ffffea, 2-6 #999980,#ffffea, 7-13 #000000,#ffffea, 14-99 d,#ffffea,
 |14: 0-0 d,#99994c, 1-1 d,#ffffea, 2-6 #999980,#ffffea, 7-13 #000000,#ffffea, 14-99 d,#ffffea,
 |15: 0-0 d,#99994c, 1-1 d,#ffffea, 2-6 #999980,#ffffea, 7-13 #000000,#ffffea, 14-99 d,#ffffea,
-|16: 0-1 #ffffff,#383c54, 2-46 #000000,#eaffff, 47-99 d,#eaffff,
+|16: 0-1 #ffffff,#383c54, 2-79 #000000,#eaffff, 80-99 d,#eaffff,
 |17: 0-1 d,#ffffea, 2-6 #999980,#ffffea, 7-17 #000000,#ffffea, 18-99 d,#ffffea,
 |18: 0-0 d,#99994c, 1-1 d,#ffffea, 2-6 #999980,#ffffea, 7-16 #000000,#ffffea, 17-99 d,#ffffea,
 |19: 0-0 d,#99994c, 1-1 d,#ffffea, 2-6 #999980,#ffffea, 7-99 #000000,#eeee9e,
@@ -372,7 +372,7 @@
 |29: 0-0 d,#99994c, 1-1 d,#ffffea, 2-6 #999980,#ffffea, 7-17 #000000,#ffffea, 18-99 d,#ffffea,
 == snap tail grid=100x30 cursor=7,28
 |New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
-|  /tmp/pardes-snap/themesel/cwd/t.txt Save New Del
+|  /tmp/pardes-snap/themesel/cwd/t.txt                               Save New Del
 |     1 line 1
 |     2 line 2
 |     3 line 3
@@ -387,7 +387,7 @@
 |    12 line 12
 |    13 line 13
 |    14 line 14
-|  /tmp/pardes-snap/themesel/cwd/+Themes New Del
+|  /tmp/pardes-snap/themesel/cwd/+Themes                                  New Del
 |   217 Theme wolf_alabaster_dark_bg
 |   218 Theme wolf_alabaster_dark_mono
 |   219 Theme wolf_alabaster_light
@@ -403,7 +403,7 @@
 |   229
 == snap picked grid=100x30 cursor=7,2
 |New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
-|  /tmp/pardes-snap/themesel/cwd/t.txt Save New Del
+|  /tmp/pardes-snap/themesel/cwd/t.txt                               Save New Del
 |     1 line 1
 |     2 line 2
 |     3 line 3
@@ -434,7 +434,7 @@
 |    28 line 28
 == style picked
 |0: 0-56 #000000,#eaffff, 57-99 d,#eaffff,
-|1: 0-1 #ffffff,#6e4fd0, 2-49 #000000,#eaffff, 50-99 d,#eaffff,
+|1: 0-1 #ffffff,#6e4fd0, 2-79 #000000,#eaffff, 80-99 d,#eaffff,
 |2: 0-1 d,#ffffea, 2-6 #000000,#eaffff, 7-12 #000000,#ffffea, 13-99 d,#ffffea,
 |3: 0-1 d,#ffffea, 2-6 #999980,#ffffea, 7-12 #000000,#ffffea, 13-99 d,#ffffea,
 |4: 0-1 d,#ffffea, 2-6 #999980,#ffffea, 7-12 #000000,#ffffea, 13-99 d,#ffffea,