revert: use "discard"/"revert" verb when reverting interactively (issue5143)
Instead of "record this change to 'FILE'?" now prompt with:
* "discard this change to 'FILE'?" when reverting to the parent of working
directory, and,
* "revert this change to 'FILE'?" otherwise.
#require docutils gettext
$ $TESTDIR/check-gendoc fr
checking for parse errors