git-gui: Add hotkeys for "Unstage from commit" and "Revert changes"
git-gui: Add hotkeys for "Unstage from commit" and "Revert changes"

Signed-off-by: Vitaly _Vi Shukela <0b226dda8a273b63904f29d9b4f8a16beb90e76e@tut.by>
Signed-off-by: Shawn O. Pearce <f01032651c12a22b2103346ba96b3b6b231f9d3c@spearce.org>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git