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, 16 insertions, 16 deletions

diff --git a/test/snapshots/ttylook.golden b/test/snapshots/ttylook.golden
index 09b54c88..3b82e3c7 100644
--- a/test/snapshots/ttylook.golden
+++ b/test/snapshots/ttylook.golden
@@ -1,6 +1,6 @@
 == snap tok1 grid=120x30 cursor=2,3
 |New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
-|  /tmp/pardes-snap/ttylook/cwd New Del                        /tmp/pardes-snap/ttylook/cwd New Del
+|  /tmp/pardes-snap/ttylook/cwd   New Del                      /tmp/pardes-snap/ttylook/cwd   New Del
 |
 |  big.txt  plain.txt  sub                                     big.txt  plain.txt  sub
 |
@@ -15,7 +15,7 @@
 |
 |
 |
-|  /tmp/pardes-snap/ttylook/cwd New Del
+|  /tmp/pardes-snap/ttylook/cwd   New Del
 |
 |  big.txt  plain.txt  sub
 |
@@ -31,7 +31,7 @@
 |
 == style tok1
 |0: 0-56 #949494,#121212, 57-119 d,#121212,
-|1: 0-1 #ffffff,#626262, 2-37 #949494,#121212, 38-59 d,#121212, 60-61 #ffffff,#262626, 62-97 #949494,#121212, 98-119 d,#121212,
+|1: 0-1 #ffffff,#626262, 2-39 #949494,#121212, 40-59 d,#121212, 60-61 #ffffff,#262626, 62-99 #949494,#121212, 100-119 d,#121212,
 |2: 0-0 d,#444444, 1-1 d,#080808, 2-59 #bdbdbd,#080808, 60-60 d,#444444, 61-61 d,#080808, 62-119 #bdbdbd,#080808,
 |3: 0-0 d,#444444, 1-1 d,#080808, 2-8 #080808,#80a0ff, 9-59 #bdbdbd,#080808, 60-60 d,#444444, 61-61 d,#080808, 62-119 #bdbdbd,#080808,
 |4: 0-0 d,#444444, 1-1 d,#080808, 2-59 #bdbdbd,#080808, 60-60 d,#444444, 61-61 d,#080808, 62-119 #bdbdbd,#080808,
@@ -46,7 +46,7 @@
 |13: 0-0 d,#444444, 1-1 d,#080808, 2-59 #bdbdbd,#080808, 60-60 d,#444444, 61-61 d,#080808, 62-119 #bdbdbd,#080808,
 |14: 0-0 d,#444444, 1-1 d,#080808, 2-59 #bdbdbd,#080808, 60-60 d,#444444, 61-61 d,#080808, 62-119 #bdbdbd,#080808,
 |15: 0-0 d,#444444, 1-1 d,#080808, 2-59 #bdbdbd,#080808, 60-60 d,#444444, 61-61 d,#080808, 62-119 #bdbdbd,#080808,
-|16: 0-1 #ffffff,#262626, 2-37 #949494,#121212, 38-59 d,#121212, 60-60 d,#444444, 61-61 d,#080808, 62-119 #bdbdbd,#080808,
+|16: 0-1 #ffffff,#262626, 2-39 #949494,#121212, 40-59 d,#121212, 60-60 d,#444444, 61-61 d,#080808, 62-119 #bdbdbd,#080808,
 |17: 0-0 d,#444444, 1-1 d,#080808, 2-59 #bdbdbd,#080808, 60-60 d,#444444, 61-61 d,#080808, 62-119 #bdbdbd,#080808,
 |18: 0-0 d,#444444, 1-1 d,#080808, 2-59 #bdbdbd,#080808, 60-60 d,#444444, 61-61 d,#080808, 62-119 #bdbdbd,#080808,
 |19: 0-0 d,#444444, 1-1 d,#080808, 2-59 #bdbdbd,#080808, 60-60 d,#444444, 61-61 d,#080808, 62-119 #bdbdbd,#080808,
@@ -62,7 +62,7 @@
 |29: 0-0 d,#444444, 1-1 d,#080808, 2-59 #bdbdbd,#080808, 60-60 d,#444444, 61-61 d,#080808, 62-119 #bdbdbd,#080808,
 == snap tok2 grid=120x30 cursor=11,3
 |New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
-|  /tmp/pardes-snap/ttylook/cwd New Del                        /tmp/pardes-snap/ttylook/cwd New Del
+|  /tmp/pardes-snap/ttylook/cwd   New Del                      /tmp/pardes-snap/ttylook/cwd   New Del
 |
 |  big.txt  plain.txt  sub                                     big.txt  plain.txt  sub
 |
@@ -77,7 +77,7 @@
 |
 |
 |
-|  /tmp/pardes-snap/ttylook/cwd New Del
+|  /tmp/pardes-snap/ttylook/cwd   New Del
 |
 |  big.txt  plain.txt  sub
 |
@@ -93,7 +93,7 @@
 |
 == snap tokback grid=120x30 cursor=2,3
 |New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
-|  /tmp/pardes-snap/ttylook/cwd New Del                        /tmp/pardes-snap/ttylook/cwd New Del
+|  /tmp/pardes-snap/ttylook/cwd   New Del                      /tmp/pardes-snap/ttylook/cwd   New Del
 |
 |  big.txt  plain.txt  sub                                     big.txt  plain.txt  sub
 |
@@ -108,7 +108,7 @@
 |
 |
 |
-|  /tmp/pardes-snap/ttylook/cwd New Del
+|  /tmp/pardes-snap/ttylook/cwd   New Del
 |
 |  big.txt  plain.txt  sub
 |
@@ -124,7 +124,7 @@
 |
 == snap insert grid=120x30 cursor=4,3
 |New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
-|  /tmp/pardes-snap/ttylook/cwd New Del                        /tmp/pardes-snap/ttylook/cwd New Del
+|  /tmp/pardes-snap/ttylook/cwd   New Del                      /tmp/pardes-snap/ttylook/cwd   New Del
 |
 |  nnbig.txt  plain.txt  sub                                   big.txt  plain.txt  sub
 |
@@ -139,7 +139,7 @@
 |
 |
 |
-|  /tmp/pardes-snap/ttylook/cwd New Del
+|  /tmp/pardes-snap/ttylook/cwd   New Del
 |
 |  big.txt  plain.txt  sub
 |
@@ -155,7 +155,7 @@
 |
 == snap tok3 grid=120x30 cursor=22,3
 |New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
-|  /tmp/pardes-snap/ttylook/cwd New Del                        /tmp/pardes-snap/ttylook/cwd New Del
+|  /tmp/pardes-snap/ttylook/cwd   New Del                      /tmp/pardes-snap/ttylook/cwd   New Del
 |
 |  big.txt  plain.txt  sub                                     big.txt  plain.txt  sub
 |
@@ -170,7 +170,7 @@
 |
 |
 |
-|  /tmp/pardes-snap/ttylook/cwd New Del
+|  /tmp/pardes-snap/ttylook/cwd   New Del
 |
 |  big.txt  plain.txt  sub
 |
@@ -186,7 +186,7 @@
 |
 == snap diropen grid=120x30 cursor=4,7
 |New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
-|  /tmp/pardes-snap/ttylook/cwd New Del                        /tmp/pardes-snap/ttylook/cwd New Del
+|  /tmp/pardes-snap/ttylook/cwd   New Del                      /tmp/pardes-snap/ttylook/cwd   New Del
 |
 |  big.txt  plain.txt  sub                                     big.txt  plain.txt  sub
 |
@@ -201,7 +201,7 @@
 |
 |
 |
-|  /tmp/pardes-snap/ttylook/cwd New Del
+|  /tmp/pardes-snap/ttylook/cwd   New Del
 |
 |  big.txt  plain.txt  sub
 |
@@ -217,7 +217,7 @@
 |
 == snap noop grid=120x30 cursor=4,7
 |New Newcol Find Grep Help Tutor Dump NextColor Debug Kill
-|  /tmp/pardes-snap/ttylook/cwd New Del                        /tmp/pardes-snap/ttylook/cwd New Del
+|  /tmp/pardes-snap/ttylook/cwd   New Del                      /tmp/pardes-snap/ttylook/cwd   New Del
 |
 |  big.txt  plain.txt  sub                                     big.txt  plain.txt  sub
 |
@@ -232,7 +232,7 @@
 |
 |
 |
-|  /tmp/pardes-snap/ttylook/cwd New Del
+|  /tmp/pardes-snap/ttylook/cwd   New Del
 |
 |  big.txt  plain.txt  sub
 |