an output pane is not a document: +Search/+Help split below the pane that asked, never into a column of their own

placeDoc classified any file pane as a doc, so a +Search opened from a lone
shell took layoutInsertColumn(0) - a whole new leftmost column, shoving every
existing column sideways - and an open results list was then eligible as the
split parent for a real file, stacking documents under the list. An output
buffer has no file behind it and no Save; it is the result list belonging to
the pane that asked for it. Now it is that on both sides of the rule: it
splits below from_id whatever kind of pane that is (a source that died falls
back to stackDocLeft, the same last resort a full column bar uses), and it is
skipped when a real doc hunts for its split parent, so a file opened from a
search row joins the docs instead of the results.

Real docs are untouched: fsearch/rsearch/look-file/tutor/lookpanes all pass
unchanged. psearch is the proof - its results snap was two columns (the shell
pushed to x=70, its gutter run at 70-71) and is now one 140-wide column with
the +Search stacked below at the same x origin.

1 files changed, 13 insertions, 5 deletions

diff --git a/test/snapshots/psearch.snap b/test/snapshots/psearch.snap
index 4c5e74d0..77ba294b 100644
--- a/test/snapshots/psearch.snap
+++ b/test/snapshots/psearch.snap
@@ -4,6 +4,12 @@
 # behind it, so its tag has no Save — and point at `@p0:LINE`, the look target
 # that names a live pane, since a terminal has no path. n/N walk the buffer
 # and look each row, scrolling the terminal to that line of its scrollback.
+#   PLACEMENT, and this script is the proof: an output buffer is NOT a document
+# — it is the result list of the pane that asked for it — so even here, with no
+# doc pane in the session for it to join, it does NOT take a column of its own.
+# It splits BELOW the shell it came from: every snap below stays ONE column,
+# the shell's tag and the +Search tag both starting at x=0, thirty rows split
+# between them, and nothing shifts sideways.
 start 30 140
 wait 8000 Kill Newcol
 stable 700 20000
@@ -51,18 +57,20 @@ stable 400 5000
 snap nomatch
 # right-clicking a word that names no file is the same search (acme button 3),
 # but NOT in tty mode: there the click belongs to the program on the other end,
-# so the buffer stays empty
+# so the buffer stays empty. Col 5 row 4 is the `M` of the first `x MARK a`,
+# in the shell's body in both modes (normal hides the prompt row, leaving it
+# blank, so the output rows sit at the same place either way).
 key c-b
 stable 600 8000
-press right 75 4
-release right 75 4
+press right 5 4
+release right 5 4
 stable 700 10000
 snap ttyinert
 # back in normal mode the same click searches for MARK
 key c-b
 stable 600 8000
-press right 75 4
-release right 75 4
+press right 5 4
+release right 5 4
 wait 10000 @p0:2:3
 stable 700 15000
 snap rightsearch