Update buffer's chars-modified tick when inserting from gap

* src/insdel.c (insert_from_gap): Update buffer's chars-modified
tick.  (Bug#56393)

* test/src/buffer-tests.el (test-buffer-chars-modified-ticks): New
test.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/insdel.c b/src/insdel.c
index 6f180ac5800..9b292398537 100644
--- a/src/insdel.c
+++ b/src/insdel.c
@@ -1123,6 +1123,7 @@ insert_from_gap (ptrdiff_t nchars, ptrdiff_t nbytes, bool text_at_gap_tail)
   invalidate_buffer_caches (current_buffer, GPT, GPT);
   record_insert (GPT, nchars);
   modiff_incr (&MODIFF);
+  CHARS_MODIFF = MODIFF;
 
   insert_from_gap_1 (nchars, nbytes, text_at_gap_tail);