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

[Stefan Kangas]

Gregory Heytings <gregory@heytings.org> writes:

>> If you for some reason prefer to keep that branch active, can you please
>> merge the current master to it, so that the changes in narrow-to-region
>> will be on the branch?
>
> Is that feasible?  Non fast forwards are not allowed in the Emacs
> repository, so rebasing a feature branch is not possible (without using
> the workaround of deleting and recreating the branch).

Rebasing is not possible, but merging is.