Patch that adds all styles/hooks used by vcs_info to its documentation.

Two notes about this patch:

1. I didn't actually document all of them, for some I only added
placeholders.  I think that would be better than not documenting them at
all, but obviously it would be nice if the documentation were actually
written.  I don't use most of that myself (e.g., I don't use the quilt
support at all), so I think the docs would be better if someone who
actually uses the features documented them — for example, because they
would be better placed to notice edge case bugs, instead of documenting
them as features.

2. The endsitem()/startitem() hack is because otherwise the man page
version rendered badly.  It seems to render ok everywhere I check, but
it's inelegant.  Maybe the list should be converted entirely from sitem
to item?  I amn't familiar with the yodl stuff enough to say.

Daniel

P.S. All patches I sent today should be mutually non-conflicting, though
some of them touch the same files as each other so offsets are expected
(but no fuzz).