The ``re_only_desc`` regex did not match for white and characters after
``\n``, so some description-only lines weren't getting matched. In
addition, lookaheads were added to ``re_param_line`` (i.e. make sure the
type group is not followed by a new line (``\n``)). Lastly, named groups
(ala Perl regular expressions) were added for slightly improved clarity.

Co-authored-by: Hendry, Adam <adam.grant.hendry@gmail.com>