bug#56682: locked narrowing

[Eli Zaretskii]

> Date: Tue, 29 Nov 2022 19:56:30 +0200
> Cc: 56682@debbugs.gnu.org, Eli Zaretskii <eliz@gnu.org>,
>  Stefan Monnier <monnier@iro.umontreal.ca>
> From: Dmitry Gutov <dgutov@yandex.ru>
> 
> Look at the timings for dictionary-pp.json. After C-s eman:
> 
> master: ~100 ms
> ff57f30bee, or c59b8dfefa, or Emacs 28: ~20 ms
> 
> That's the regression.

The faster ones use a different major-mode, btw.