bug#34949: 27.0.50; Docstring of `vc-deduce-fileset' incomplete

[Juri Linkov]

> Thinking about that, I believe it's because the thing that vc-next-action
> does depends on the status of the files in the fileset. So the statuses
> have to be compatible.

The core concept of the proposed new command ‘C-x v V’ and ‘V’ in VC-Dired
is to deduce the fileset from the statuses of repository files, without
explicitly marking the files in VC-Dired and without using only the
current file as ‘C-x v v’ does.

Some dwim logic could be employed such as collecting only edited files
to the fileset, but I'm not sure if this will cover 100% of user needs.

Maybe some customizable variable could be added with a list of statuses
to specify what files to include to the fileset.

Foremost this feature is needed to deduce the files to include to the
fileset from a subdirectory marked in Dired after typing ‘C-x v v’ on it.