bug#50935: minibuffer-electric-default-mode interface

[Juri Linkov]

> A third option is to add 'minibuffer-default-prompt-format' on emacs-28,
> but make the suggested deletion on master -- which give us more time to
> get `minibuffer-default-prompt-format' up to scrap.
>
> Thoughts?

Thanks for adding format-prompt to many more prompts.  I noticed
that when minibuffer-default-prompt-format is customized to the
recommended format " [%s]", then the prompt of proced-send-signal
is confusing with two pairs of the same brackets:

  Send signal [3 processes] [TERM]:

The following patch makes the prompt more readable:

  Send signal to 3 processes [TERM]:

diff --git a/lisp/proced.el b/lisp/proced.el
index 29996068f9..cb66d68302 100644
--- a/lisp/proced.el
+++ b/lisp/proced.el
@@ -1773,7 +1773,7 @@ proced-send-signal
            `(:annotation-function
              ,(lambda (s) (cdr (assoc s proced-signal-list))))))
      (proced-with-processes-buffer process-alist
-       (list (completing-read (format-prompt "Send signal [%s]"
+       (list (completing-read (format-prompt "Send signal to %s"
                                              "TERM" pnum)
                               proced-signal-list
                               nil nil nil nil "TERM")
@@ -1798,7 +1798,7 @@ proced-send-signal
              `(:annotation-function
                ,(lambda (s) (cdr (assoc s proced-signal-list))))))
         (proced-with-processes-buffer process-alist
-          (setq signal (completing-read (format-prompt "Send signal [%s]"
+          (setq signal (completing-read (format-prompt "Send signal to %s"
                                                        "TERM" pnum)
                                         proced-signal-list
                                         nil nil nil nil "TERM"))))))