bug#37802: 27.0.50; Feature request: hook for theme enabling/disabling

[Eli Zaretskii <eliz@gnu.org>]

> Resent-From: Lars Ingebrigtsen <larsi@gnus.org>
> Original-Sender: "Debbugs-submit" <debbugs-submit-bounces@debbugs.gnu.org>
> Resent-CC: bug-gnu-emacs@gnu.org
> Resent-Sender: help-debbugs@gnu.org
> Cc: 37802@debbugs.gnu.org
> From: Lars Ingebrigtsen <larsi@gnus.org>
> Date: Sat, 21 May 2022 14:56:34 +0200
> 
> Óscar Fuentes <ofv@wanadoo.es> writes:
> 
> > Currently I've solved my requirement by using defadvice on enable-theme
> > *and* disable-theme for adapting my custom faces to changes on the
> > active theme(s). Using a hook would be a little bit cleaner. I'm also
> > surprised that no hook was implemented for this case, as most changes on
> > user-visible state has an associated hook.
> 
> Yes, true.  So I've now added these two hooks to Emacs 29.

Thanks, but is there any reason these hooks aren't called
enable-theme-function and disable-theme-function?  Hooks by such
names are already documented as "abnormal hooks", which would avoid
the need of saying these new hooks are "atypical", something that we
never had in our terminology.