bug#34525: replace-regexp missing some matches

[Eli Zaretskii]

> From: Stefan Monnier <monnier@IRO.UMontreal.CA>
> Cc: Alan Mackenzie <acm@muc.de>, daniel.lopez999@gmail.com,
>         34525@debbugs.gnu.org
> Date: Wed, 27 Feb 2019 12:41:04 -0500
> 
> AFAICT the only place where the missing updates can bite us is when we
> call update_interval, since it seems to be the only function that relies
> on all parents having the ->position field correctly set.
> 
> update_interval is only called from update_syntax_table.

That I could understand.  But then the fix should be in that one
function (if we keep it).