python: Fix broken ReST docstrings

This patch *doesn't* update all of the docstring standards across the
QEMU package directory to make our docstring usage consistent. It
*doesn't* fix the formatting to make it look pretty or reasonable in
generated output. It *does* fix a few small instances where Sphinx would
emit a build warning because of malformed ReST -- If we built our Python
docs with Sphinx.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Willian Rampazzo <willianr@redhat.com>
Reviewed-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Message-id: 20210629214323.1329806-16-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>