bug#49162: 28.0.50; [PATCH] Use named face for apropos-face-button

[Eli Zaretskii]

> From: Protesilaos Stavrou <info@protesilaos.com>
> Cc: 49162@debbugs.gnu.org
> Date: Tue, 22 Jun 2021 15:11:33 +0300
> 
> Thank you Martin and Eli!  I picked that symbol because it was already
> given by the implicit face.
> 
> You can try it with emacs -Q:
> 
> - M-x apropos RET font-lock-variable RET
> - Place point over the underlined "Face" text and M-x describe-char
> - In the resulting Help buffer, you will find the reference to
>   'apropos-face-button', whose specification is defined thus:
> 
>     Category apropos-face-button:

That's the _button_, not its _face_.  It is cumbersome to call a face
by a name that ends with "-button", IMO.