Pygments and Sphinx get pickier all the time; Sphinx 2.1+ now catches
these errors.

Signed-off-by: John Snow <jsnow@redhat.com>
Reported-by: Aarushi Mehta <mehta.aaru20@gmail.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20190603214653.29369-2-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>