bug#67062: 30.0.50; [PATCH] Abbreviate the revision in 'vc-annotate' (for Git)

[Eli Zaretskii]

> Date: Sun, 12 Nov 2023 11:07:38 -0800
> Cc: 67062@debbugs.gnu.org
> From: Jim Porter <jporterbugs@gmail.com>
> 
> In any case, we don't necessarily need to provide a default 
> implementation for the 'short-revision' function. What about something 
> like this? I'm not sure it's better, but it does let us avoid defining a 
> no-op implementation for the "default backend".

Fine by me, except that I think this should be optional behavior.