bug#55940: macOS: <ns-show-prefs> displayed as keybinding for \\[customize]

["Daniel Martín via Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

Po Lu <luangruo@yahoo.com> writes:

> Stefan Kangas <stefan@marxist.se> writes:
>
>> Aha, thanks.  I can't find it in '(emacs) Mac / GNUstep Events' but I
>> might be missing something.  (Also: The other events there seem to be
>> missing index entries; maybe we would want to add such entries.)
>
> Done.
>
>> Adding this event to the manual is useful, but I still think that, for
>> the purposes of command substitution, it would be better to display an
>> actual keybinding rather than an event.
>
> I have no opinion towards that, since I don't actually use Mac OS.

I think it's fine to only update the documentation.  We can expand the
text a bit and say that <ns-open-prefs> is usually sent by the OS when
Emacs is the front process and the user presses `Cmd-,' (comma).  This
is officially documented, at least for macOS
(https://support.apple.com/en-us/HT201236).  Similarly, we already say
that the fonts panel event is sent with `Cmd-t`.

If we had common events indexed in the manuals, users could ask Emacs
about any of them with C-h S, for example.  Improving the
self-documenting features in Emacs is an alternative that I like more
compared to changing the displayed text depending on if there's only
events and no keybindings bound to a function, for example.