tests/test-gendoc-it.t

statecheck: added support for STATES

This removes `STATES` from `state.py` and adds support to
`statecheck` class to handle its features.
`getrepostate()` function is modified accordingly.

This adds a method 'cmdutil.addunfinished()' for appending to
the unfinishedstate list so as to keep 'merge' and 'bisect' at the last.

This also makes two separate message formats for `checkunfinished()` and
`getrepostate()` as there were previously present.

Results of test changed are shown.

Differential Revision: https://phab.mercurial-scm.org/D6503

#require docutils gettext

  $ $TESTDIR/check-gendoc it
  checking for parse errors