Backport commit 6a3920c07 from Emacs

* lisp/org-agenda.el (org-agenda-get-restriction-and-command):
Using `error' here will trigger users with `debug-on-error' so use
`user-error' instead (bug#49920).  It would probably be preferable
to rewrite this to not use the error system to do control flow.

Make `q' in `org-agenda' work even with `debug-on-error' set
6a3920c07eaae58408dd27e7db22bff7ad4d1f80
Lars Ingebrigtsen
Sat Aug 7 12:55:39 2021 +0200

lisp/org-agenda.el

@@ -3205,7 +3205,7 @@ s   Search for keywords                 M   Like m, but only TODO entries
             (delete-window)
             (org-agenda-get-restriction-and-command prefix-descriptions))
 
-	   ((equal c ?q) (error "Abort"))
+	   ((equal c ?q) (user-error "Abort"))
 	   (t (user-error "Invalid key %c" c))))))))
 
 (defun org-agenda-fit-window-to-buffer ()