L2SS-558: Perform linting on sphinx rst files

Ignore lines going over 80 characters as the majority of the team
does not mind long lines.

tangostationcontrol/tox.ini

@@ -29,8 +29,7 @@ commands =
 ; TODO(Corne): Integrate Hacking to customize pep8 rules
 [testenv:pep8]
 commands =
-; doc8 is only necessary in combination with Sphinx or ReStructuredText (RST)
-;    doc8 doc/source/ README.rst
+    doc8 docs/source/ --ignore D001
     flake8
 
 [testenv:bandit];