bug#53874: Patch: make set-fill-column show the current fill-column

[Antoine Levitt]

> Instead of doing it this way, I think it might make more sense to just
> change the prompt to "Change fill-column from %s to:" instead?  People
> may have set minibuffer-default-prompt-format to something weird.

Good idea and much simpler than what I did ! Here's the patch.

diff --git a/lisp/simple.el b/lisp/simple.el
index dd48039..247f68d 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -8258,7 +8258,7 @@ set-fill-column
              ;; We used to use current-column silently, but C-x f is too easily
              ;; typed as a typo for C-x C-f, so we turned it into an error and
              ;; now an interactive prompt.
-             (read-number "Set fill-column to: " (current-column)))))
+             (read-number (format "Change fill-column from %s to: " 
fill-column) (current-column)))))
   (if (consp arg)
       (setq arg (current-column)))
   (if (not (integerp arg))