master f2dfe1e 1/3: Merge from origin/emacs-28

[Glenn Morris]

branch: master
commit f2dfe1e780f0a779f50650fcf457b33031fa9584
Merge: d1e4d89 817c929
Author: Glenn Morris <rgm@gnu.org>
Commit: Glenn Morris <rgm@gnu.org>

    Merge from origin/emacs-28
    
    817c929eda Doc fix for concat
    3eca2ad2a1 * lisp/image-dired.el (image-dired-external-viewer): Suppo...
---
 lisp/image-dired.el | 5 +++--
 src/fns.c           | 3 +++
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/lisp/image-dired.el b/lisp/image-dired.el
index 77a3590..9313c62 100644
--- a/lisp/image-dired.el
+++ b/lisp/image-dired.el
@@ -544,11 +544,12 @@ with the comment."
   ;; dired-view-command-alist.
   (cond ((executable-find "display"))
         ((executable-find "xli"))
-        ((executable-find "qiv") "qiv -t"))
+        ((executable-find "qiv") "qiv -t")
+        ((executable-find "feh") "feh"))
   "Name of external viewer.
 Including parameters.  Used when displaying original image from
 `image-dired-thumbnail-mode'."
-  :version "27.1"
+  :version "28.1"
   :type '(choice string
                  (const :tag "Not Set" nil)))
 
diff --git a/src/fns.c b/src/fns.c
index 6118285..76c76c9 100644
--- a/src/fns.c
+++ b/src/fns.c
@@ -672,6 +672,9 @@ DEFUN ("concat", Fconcat, Sconcat, 0, MANY, 0,
        doc: /* Concatenate all the arguments and make the result a string.
 The result is a string whose elements are the elements of all the arguments.
 Each argument may be a string or a list or vector of characters (integers).
+
+Values of the `composition' property of the result are not guaranteed
+to be `eq'.
 usage: (concat &rest SEQUENCES)  */)
   (ptrdiff_t nargs, Lisp_Object *args)
 {