tests/test-gendoc-zh_TW.t

narrow: move checking for narrow requirement into _narrowmatch()

We want to move narrowmatch() and others into core, so we need to get
rid of the dependence on the "narrow_opts" from the closure in
narrowrepo.wraprepo(). We can simply check if the narrow requirement
is set. I think that seems like an improvement regardless of moving
narrowmatch().

Differential Revision: https://phab.mercurial-scm.org/D2489

#require docutils gettext

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