tests/test-gendoc-ru.t

revlog: add attribute on revlogs that specifies its kind

The sidedata logic needs to check whether the revlog it's working on is a
changelog, a manifest or a filelog.
Furthermore, future versions of the revlog format will most likely see a split
between the three types (i.e. they will store different information), so having
this will be useful for other future endeavors as well.

Differential Revision: https://phab.mercurial-scm.org/D10151

#require docutils gettext

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