Merge pull request #6269 from blueyed/docs

tox: docs: --keep-going and posargs

Author: blueyed

tox.ini

@@ -60,9 +60,8 @@ basepython = python3
 usedevelop = True
 changedir = doc/en
 deps = -r{toxinidir}/doc/en/requirements.txt
-
 commands =
-    sphinx-build -W -b html . _build
+    sphinx-build -W --keep-going -b html . _build {posargs:}
 
 [testenv:docs-checklinks]
 basepython = python3