tests/test-check-config.t

graft: clarify in help that `-r` is not just optional

Positional parameters are also treated as revisions, but the order of revisions
matters and it will often be wrong if the user understands it as `-r` taking
multiple revisions as `-r REV1 REV2`.

(Alternatively, `-r` could be turned into a no-op flag as the documentation
suggests. That would however be less "semantic markup" and I agree with the
implementation in 55e7f352b1d3 but not the documentation.)

#require test-repo

  $ cd "$TESTDIR"/..

New errors are not allowed. Warnings are strongly discouraged.

  $ hg files "set:(**.py or **.txt) - tests/**" | sed 's|\\|/|g' |
  >   xargs python contrib/check-config.py