bug#50572: 28.0.50; [PATCH] fix VC to find the responsible backend with the most specific path.

[Eli Zaretskii]

> Cc: 50572@debbugs.gnu.org
> From: Dmitry Gutov <dgutov@yandex.ru>
> Date: Wed, 15 Sep 2021 13:41:57 +0300
> 
> Now, the change in vc-responsible-backend might seem controversial, as 
> it decreases customizability and performance (a bit), but it was made a 
> year ago, and we've received no substantial complaints. And there have 
> been multiple reports (all linked) about the previous behavior.

That doesn't alleviate my worries, unfortunately.  Many people either
don't use VC or use it very "narrowly", so they never bump into these
rarely-used-but-very-useful features.