bug#66394: 29.1; Make register-read-with-preview more useful

[Eli Zaretskii]

> From: Thierry Volpiatto <thievol@posteo.net>
> Cc: monnier@iro.umontreal.ca,  michael_heerdegen@web.de,
>   stefankangas@gmail.com,  66394@debbugs.gnu.org
> Date: Sat, 02 Dec 2023 05:51:45 +0000
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > Anyway, I trust you to do what is needed here, I just want the test
> > suite to keep running successfully, and I don't have time to work on
> > this myself.  TIA.
> 
> Here again the patchs (0002 with a little modification).
> Let me know if I can commit them.

Please install on the master branch, and thanks.