Make command, lisp, perl, python, and ruby tags interpret "markup".

Make command, lisp, perl, python, and ruby tags interpret "markup".

* lisp/muse-publish.el (muse-publish-markup-tags): Permit <lisp> to take
  the "markup" argument.
  (muse-publish-markup-attribute): New macro that interprets the "markup"
  attribute.
  (muse-publish-lisp-tag, muse-publish-command-tag): Use
  muse-publish-markup-attribute.
  (muse-publish-command-tag): Make sure we have a newline at end of
  output.
  (muse-publish-perl-tag, muse-publish-python-tag)
  (muse-publish-ruby-tag): Pass remaining attributes to
  muse-publish-command-tag so that the "markup" attribute works.
  (muse-publish-include-tag): Use muse-publish-markup-attribute.

* muse.texi (Tag Summary): Document changes to tags.
git-archimport-id: mwolson@gnu.org--2006/muse--main--1.0--patch-173