bug#60569: 29.0.60; vc-pull-and-push unsupported on non-git vcs

[Eli Zaretskii]

> From: Juri Linkov <juri@linkov.net>
> Cc: 60569@debbugs.gnu.org
> Date: Tue, 24 Jan 2023 19:49:24 +0200
> 
> > Looks OK to me, but could you add some details regarding why this
> > change is needed?  Did we change our requirements from the return
> > value of the pushpull method?
> 
> Yes, to support vc-pull-and-push now the backend should return the
> process for the pull operation.  Here is the improved documentation:

Thanks, this is okay for the emacs-29 branch.