bug#57400: 29.0.50; Support sending patches from VC directly

[Lars Ingebrigtsen]

Juri Linkov <juri@linkov.net> writes:

> Not only vc-log-outgoing, but also another useful command to show
> the log to be able to mark commits in it for preparing a patch,
> is `C-x v M L' (vc-log-mergebase) that shows the log of all changes
> in the branch.  So I'd rather turn `C-x v l' into a prefix key.

I think `C-x v l' is one of the more commonly used commands, so changing
it would probably be annoying.