bug#51016: 28.0.50; 'diff-font-lock-prettify' breaks display of outline headers

[Eli Zaretskii]

> From: Juri Linkov <juri@linkov.net>
> Cc: Eli Zaretskii <eliz@gnu.org>,  51016@debbugs.gnu.org,  larsi@gnus.org,
>   orontee@gmail.com
> Date: Sat, 18 Dec 2021 19:05:52 +0200
> 
> > As a user, I still consider that Emacs tripping over form feeds
> > when I ask it to go to the next heading is a plain bug
> 
> Indeed, it's a plain bug: when the new variable outline-minor-mode-use-buttons
> is enabled, ^L lines displayed as outline headings are making a mess:

I guess I'm blind, since I see neither a bug nor a mess.