bug#57807: 29.0.50; Make vc-print-branch-log able to log multiple branches

[Juri Linkov]

>>> That seems alright.  Maybe we could use some symbol, e.g. '$' or '#',
>>> instead of a letter 'c', to distinguish its special status.
>>
>> I see that 'c' might clash with a possible future command.
>> For example, git has a lot of commands whose names start
>> with the letter 'c': checkout, cherry-pick, clone, commit, ...
>> So the probability of the need to use 'c' is high.
>>
>> OTOH, what key would keep the mnemonic of a prefix arg?
>> Maybe 'C-x v C-u'?
>
> Might be confusing if you need to do C-u C-x v C-u C-x v b l ...
>
> '$' and '!' have shell command mnemonics.

I didn't recognize '$' and '#' as shell-related symbols here
because in Emacs they have another semantics: e.g.
'C-x #' is 'server-edit', 'M-$' is ispell-checking, etc.

But 'M-!' has a clear connection with editing a shell command.  So
'C-x v !' looks like the best candidate among all considered so far.