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

[Ihor Radchenko]

Eli Zaretskii <eliz@gnu.org> writes:

>> I have seen very long lines in Org. Specifically, in source block
>> output. (http query)
>
> How long is "very long" in those cases?

AFAIR, over a screen full of text when truncate-lines is set to nil.
It should be over 5k symbols in my screen.

I remember this because it triggered a significant fontification
slowdown caused by some (now fixed) Org regexp hitting too many matches
on that line.

Also, I just checked some of my org files and found a >15k chars long line.

-- 
Ihor Radchenko,
Org mode contributor,
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