crecord: re-enable reviewing a patch before comitting it The "r" option for this feature was copied into Mercurial from crecord, but the actual implementation never made it into hg until now. It's a moderately useful feature that allows the user to edit the patch in a text editor before comitting it for good. This requires a test, so we must also enable a corresponding testing 'R' option that skips the confirmation dialogue. In addition, we also need a help text for the editor when reviewing the final patch. As for why this is a useful feature if we can already edit hunks in an editor, I would like to offer the following points: * editing hunks does not show the entire patch all at once ** furthermore, the hunk "tree" in the TUI has no root that could be selected for edition * it is helpful to be able to see the entire final patch for confirmation ** within this view, the unselected hunks are hidden, which is visusally cleaner ** this works as a final review of the complete result, which is a bit more difficult to do conceptually via hunk editing * this feature was already in crecord, so it was an oversight to not bring it to core * it works and is consistent with editing hunks