adds an allfiles flag that lets you grep on all files in the revision
and not just the one that were modified in that changeset.
This would work on a single revision and get all the files that were
there in that revision. So it's like grepping on a previous state.
Using this with wdir() :: hg grep -r "wdir()" --allfiles is what the
default behaviour is desired for grep.
Support for multiple revisions to be added later
I wonder if --allfiles is a better name. --unmodified makes me think unmodified files exclusively.
It's too bad --all is already used, because that would be consistent with the all files meaning in status and revert. (Maybe others?) The plan page mentions BCing plain grep into oblivion, and deprecating --all. Is it worth a BC on this too, for consistency going forward?