Add negative tests doc-bad-enum-member and doc-bad-feature to cover
documentation for nonexistent enum members and features, and test
doc-undoc-feature to cover features lacking documentation. None of
them works. To be fixed later in this series.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20191024110237.30963-2-armbru@redhat.com>