tests/test-gendoc-zh_TW.t

largefiles: replace always() method, not _always field

We will soon have matchers that don't have an _always field, so
largefiles needs to stop assuming that they do. _always is only used
by always(), so we safely replace that method instead.

#require docutils gettext

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