bug#56682: Fix the long lines font locking related slowdowns

[Eli Zaretskii]

> Date: Fri, 29 Jul 2022 12:05:16 +0000
> From: Gregory Heytings <gregory@heytings.org>
> cc: gerd.moellmann@gmail.com, 56682@debbugs.gnu.org, larsi@gnus.org, 
>     monnier@iro.umontreal.ca
> 
> > I didn't revert.  I've changed back only some parts of the changes you 
> > made, and left others as you changed them.
> 
> You did revert the only change of which I said it was important to me

I understand that it's important to you, and understood that the first
time, but I cannot let our documentation say things that I'm unable to
defend in good faith.  When the dust settles and all is said and done,
it is only us the maintainers who are left to defend the decisions we
made as a project.  Please try to see this from our POV as well.