bug#74673: 30.0.92; face warning on legal elisp syntax

[Eli Zaretskii <eliz@gnu.org>]

> From: Robert Pluim <rpluim@gmail.com>
> Cc: Kévin Le Gouguec <kevin.legouguec@gmail.com>,
>   christopher@librehacker.com,  74673@debbugs.gnu.org
> Date: Thu, 05 Dec 2024 10:28:55 +0100
> 
> >>>>> On Wed, 04 Dec 2024 19:32:54 +0200, Eli Zaretskii <eliz@gnu.org> said:
> 
>     >> From: Kévin Le Gouguec <kevin.legouguec@gmail.com>
>     >> Cc: Christopher Howard <christopher@librehacker.com>,  74673@debbugs.gnu.org
>     >> Date: Wed, 04 Dec 2024 18:12:06 +0100
>     >> 
>     >> Eli Zaretskii <eliz@gnu.org> writes:
>     >> 
>     >> > Some nice features of the UI need the mouse, yes, and there's no
>     >> > (easy) way around that.  That said, you can go to the "" part and type
>     >> > "M-x describe-text-properties", which will pop a buffer that tells you
>     >> > there's a help-echo property at that spot, and show a button which you
>     >> > could press to have the text shown in the echo-area.
>     >> >
>     >> > If you really need to be able to show tool tips without the mouse, you
>     >> > can write a simple function to show its text in the echo-area.
>     >> > However, most tooltips are shown on UI parts where you cannot go, so
>     >> > such a command will be of somewhat limited use.
>     >> 
>     >> Apologies if I missed something: this specific diagnostic is also
>     >> visible with 'C-h .', right?
> 
>     Eli> Yes.
> 
> You could do something like this to economise on typing:
> 
> (defun display-help-string ()
>     (when-let* ((help (help-at-pt-kbd-string)))
>       (message "%s" (substitute-command-keys help))))
> (add-hook 'post-command-hook #'display-help-string nil t)
> 
> (hmm, would it make sense to add something like that to eldoc?)

Given that we already have help-at-pt-display-when-idle, why is
anything else needed?