Make format-prompt' use substitute-command-keys'

* doc/lispref/minibuf.texi (Text from Minibuffer): Mention it.
* lisp/minibuffer.el (format-prompt): Run through
`substitute-command-keys' (bug#51040).

doc/lispref/minibuf.texi

@@ -490,6 +490,9 @@ If @var{default} is @code{nil}, there is no default value, and
 therefore no ``default value'' string is included in the result value.
 If @var{default} is a non-@code{nil} list, the first element of the
 list is used in the prompt.
+
+Both @var{prompt} and @code{minibuffer-default-prompt-format} are run
+through @code{substitute-command-keys} (@pxref{Keys in Documentation}).
 @end defun
 
 @defvar read-minibuffer-restore-windows

etc/NEWS

@@ -2450,6 +2450,11 @@ when visiting JSON files.
 
 * Incompatible Lisp Changes in Emacs 29.1
 
++++
+** 'format-prompt' now uses 'substitute-command-keys'.
+This means that both the prompt and 'minibuffer-default-prompt-format'
+will have key definitions and single quotes handled specially.
+
 ---
 ** 'find-image' now uses 'create-image'.
 This means that images found through 'find-image' also have

lisp/minibuffer.el

@@ -4461,6 +4461,11 @@ FORMAT-ARGS is non-nil, PROMPT is used as a format control
 string, and FORMAT-ARGS are the arguments to be substituted into
 it.  See `format' for details.
 
+Both PROMTP and `minibuffer-default-prompt-format' are run
+through `substitute-command-keys' (which see).  In particular,
+this means that single quotes may be adjusted for the current
+terminal.
+
 If DEFAULT is a list, the first element is used as the default.
 If not, the element is used as is.
 
@@ -4468,12 +4473,12 @@ If DEFAULT is nil or an empty string, no \"default value\" string
 is included in the return value."
   (concat
    (if (null format-args)
-       prompt
-     (apply #'format prompt format-args))
+       (substitute-command-keys prompt)
+     (apply #'format (substitute-command-keys prompt) format-args))
    (and default
         (or (not (stringp default))
             (length> default 0))
-        (format minibuffer-default-prompt-format
+        (format (substitute-command-keys minibuffer-default-prompt-format)
                 (if (consp default)
                     (car default)
                   default)))