bug#68352: 29.1; gnus-message-citation-mode removes values from font-lock-keywords

[Eli Zaretskii]

> Cc: 68352@debbugs.gnu.org
> From: Morgan Willcock <morgan@ice9.digital>
> Date: Thu, 11 Jan 2024 11:57:36 +0000
> 
> I've attached a patch which is essentially the same as Eric's suggestion
> except that, the original comment is kept, the HOW argument of
> `font-lock-add-keywords' is set to t, and the code is restructured to
> avoid any font-lock changes until `font-lock-mode' is active.

Eric, how should we go about making some progress here?  Should the
proposed patch be installed?

Thanks.