tests/test-gendoc-pt_BR.t

revlog: add a method to tells whether rev is stored as a snapshot

For now we only have one type of snapshot: full snapshot versus nullrev.
However we are looking into adding intermediate snapshot where a large diff
against another snapshot is performed instead of storing a full new text.

The conditional is a bit strange and is done in order to help readability of a
some later changesets.

#require docutils gettext

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