Sphinx: A warning on using recommonmark

[jfbu]

Describe the bug
When using current recommonmark extension installed in a virtualenv by pip install I get seemingly systematically

/Users/xxx/yyy/sphinxvenv/lib/python3.6/site-packages/recommonmark/parser.py:65: UserWarning: Container node skipped: type=document
  warn("Container node skipped: type={0}".format(mdnode.t))

Got it on two projects. One with old way (deprecated) of using recommonmark, the other one following our guidelines

Environment info

• OS: Mac
• Python version: 3.6.8
• Sphinx version: 2.0.2+
• Sphinx extensions: recommonmark

I suppose I should report to recommonmark project...

[tk0miya]

The warning is emitted inside recommonmark. So there are nothing to do from sphinx side.
https://github.com/rtfd/recommonmark/blob/815d75ea503f30af26ab67c6820078f84875b1fc/recommonmark/parser.py#L64-L65

[tk0miya]

Closing.

[jacobtomlinson]

This issue has been raised over on recommonmark, linking for others that land here.

readthedocs/recommonmark#177