bug#31325: 27.0.50; PROPOSAL: introduce a new function to recenter without redisplaying the frame

[Eli Zaretskii]

> From: John Shahid <jvshahid@gmail.com>
> Cc: rudalics@gmx.at, 31325-done@debbugs.gnu.org, monnier@iro.umontreal.ca
> Date: Sun, 01 Jul 2018 16:54:53 +0000
> 
> It just occurred to me that this change will break backward
> comparability for those who bind some key to the `recenter' command,
> since now the second argument will always be nil and thus won't
> redisplay.  Should we also change the interactive form of recenter to
> use "p" for the second argument?  That way the second arg is never nil
> when used interactively.

I think you are right.

Alternatively, we could simply make 'recenter' behave specially in
interactive invocations.  But in any case, incompatible changes in
behavior are bad, and should be avoided.