tests/test-gendoc-zh_CN.t

resourceutil: use `from importlib import resources`

Without this patch, we get the following error from when trying to run
hg with PyOxidizer:

  module 'importlib' has no attribute 'resources'

I don't know what why that happens, but `from importlib import
resources` is the form I would prefer anyway, so let's use that now
that the impoort-checker has been fixed.

Differential Revision: https://phab.mercurial-scm.org/D7701

#require docutils gettext

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