bug#36861: 27.0.50; display-fill-column-indicator-mode in log-edit-mode

[Juri Linkov]

It has an unpleasant effect when git commit abruptly fails when
the length of the first line of the commit message is longer than
78 characters.  This patch enables a visual indication in the
log-edit buffer to help not to exceed the limit beforehand:

diff --git a/.dir-locals.el b/.dir-locals.el
index ffd65c8802..e56d8c753b 100644
--- a/.dir-locals.el
+++ b/.dir-locals.el
@@ -10,7 +10,9 @@
                (electric-quote-comment . nil)
                (electric-quote-string . nil)))
  (log-edit-mode . ((log-edit-font-lock-gnu-style . t)
-                   (log-edit-setup-add-author . t)))
+                   (log-edit-setup-add-author . t)
+                   (fill-column . 78)
+                   (eval . (display-fill-column-indicator-mode))))
  (change-log-mode . ((add-log-time-zone-rule . t)
                     (fill-column . 74)
                     (eval . (bug-reference-mode))))