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

[Eli Zaretskii]

> Date: Tue, 16 Aug 2022 12:42:04 +0000
> From: Gregory Heytings <gregory@heytings.org>
> cc: 56682@debbugs.gnu.org, monnier@iro.umontreal.ca, dgutov@yandex.ru
> 
> 
> >>>> Adding such a variable only two weeks after locked narrowing has been 
> >>>> introduced means that modes will have little incentive to adapt to 
> >>>> that stronger constraint, if they can "fix" whatever problems that 
> >>>> constraint might cause by setting that variable to nil in their 
> >>>> initialization hooks.
> >>>
> >>> Modes can do that already by changing long-line-threshold to nil, 
> >>> don't they?
> >>
> >> They can indeed, but that variable is documented as "for debugging 
> >> purposes" only.
> >
> > That never stopped anyone, IME.
> >
> 
> At least they cannot tell the haven't been warned...
> 
> Can this change at least wait a few days?

It will wait regardless, because I still have too many things on my
plate that are more important.