Help lists every builtin and every way to reach it

Not a second builtin: Help already rendered "every builtin with a leader path
and the key that runs it", and the ask is "every builtin and every shortcut" —
the same listing with three more rows and one more column. A new builtin would
have been a second renderer over a superset of the same rows, and the two would
drift the first time a column moved. The prefix filter is now the degenerate
case of the index rather than a separate mode: SPC h ? reads the same array
with prefix "h", and the path-less builtins fall out on their own because an
empty path starts with nothing.

The shortcut column is folded, never typed: chordName spells a chord from Key's
OWN declarations, so a new special key names itself and an unnamed
non-printable codepoint is a compile error instead of garbage; shortcuts()
walks the cmd columns of window_keys and jump_keys, look_cmd/exec_cmd with
their keys and buttons, and topbar_str. Retarget a binding in config.zig and
this re-renders.

So Look reads `enter, right-click`, Back reads `C-o`, Kill reads `topbar`, and
Theme reads nothing at all — which is the information.

Not a picker, deliberately: n/N stepping a list holding Kill, Del and Delcol
would end the session. The names are live text, so middle-click the one you
want.

Alt-n, Alt-c, the tty toggle and the cut/paste chords cannot appear — they are
inline handlers that reach no builtin, so there is no row to put them on. Make
one a struct with a cmd column beside its binding and it appears for free.

Three goldens moved, all of them the +Help buffer's contents.

1 files changed, 60 insertions, 0 deletions

diff --git a/test/snapshots/builtins.snap b/test/snapshots/builtins.snap
new file mode 100644
index 00000000..b2c4f752
--- /dev/null
+++ b/test/snapshots/builtins.snap
@@ -0,0 +1,60 @@
+# RULE: Help is THE INDEX of the builtins — every one of them, and every way
+# to run it — not a listing of leader paths. Three columns, all derived at
+# comptime from config.zig's own tables: the SPC path (leader_path), the name,
+# and every other shortcut bound to that name (window_keys and jump_keys' `cmd`
+# columns, look_cmd/exec_cmd with their keys and mouse buttons, a word in
+# topbar_str). A builtin added tomorrow is a row here with nothing to edit.
+#
+# The cases this exists for are the ones a leader listing could not show:
+# Look and Exec have NO SPC path — their shortcuts are Enter/Tab and the two
+# mouse buttons — and Theme has no shortcut at all, because a key path can
+# never carry the name of a theme. All three are rows, and their blank columns
+# are the information.
+#
+# `SPC ?` mid-chord is the SAME array read with a non-empty prefix, which is
+# why there is one builtin here and not two: the group filter drops the
+# path-less rows by itself, and the reference page is the filter's empty case.
+lines notes.txt 6
+start 60 120 notes.txt
+wait 8000 notes.txt
+stable 700 20000
+snap boot
+# SPC ? at the ROOT. Focus follows the listing — you asked to read it.
+key space ?
+wait 10000 SPC c n
+stable 700 15000
+snap index
+# The tail of the same listing: the window group carries BOTH spellings of
+# each Ctrl-w chord (the table carries both), and past the last path come the
+# three builtins SPC cannot reach. `ge` walks the buffer's own body to the end.
+key g e
+stable 700 15000
+snap index-tail
+# n/N here must NOT run the rows. ThemeSel's buffer executes what it steps
+# onto, and that is safe because wearing a theme is free; this list holds Kill,
+# Del and Delcol, so stepping it would end the session. Three presses, and the
+# panes and the listing are all where they were.
+key n
+key n
+key n
+stable 700 15000
+snap not-a-picker
+# and the mid-chord filter is untouched: `SPC w ?` still answers "what can w
+# still reach", rewriting the same +Help buffer with just that group — five
+# rows, each now also showing the Ctrl-w chord that is the other way in, and
+# none of the three path-less builtins, which `w` cannot reach.
+key space w ?
+wait 10000 Toggleterm
+stable 700 15000
+snap window-group
+# back to the whole index, and a NAME in it is live text like anywhere else:
+# middle-click `Tutor` and the tutor opens. That is the picking a stepping
+# picker would have done, minus running the thirty-nine rows you passed.
+key space ?
+wait 10000 SPC c n
+stable 700 15000
+press middle 20 44
+release middle 20 44
+wait 10000 PARDES TUTOR
+stable 700 15000
+snap tutor-from-index