tests/test-gendoc-el.t

import-checkers: split tests of the tool from running it on the source

We did such splits for other tools already. The 'test-check-*.t' performs the
check of the source code while the regular tests verifies the tools works.

One of the benefit is that is provides a simple file to reuse in third party
extensions.

#require docutils gettext

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