Some markdown content doesn't internationalize properly

[Bjwebb]

E.g. for https://github.com/Bjwebb/recommonmark-i18n-bug/blob/gh-pages/docs/index.md the messages I get pulled out by sphinx-build -b gettext are https://github.com/Bjwebb/recommonmark-i18n-bug/blob/gh-pages/_build/locale/index.pot - the bullet point is missing.

[Bjwebb]

Looks like this is because .source is None for some reason in the eventual doctree, and https://github.com/sphinx-doc/sphinx/blob/master/sphinx/util/nodes.py#L90 ignores such nodes.

(If I remove that if statement from sphinx, the bullet point text is outputted correctly by gettext).

[shimizukawa]

I think this issue has been fixed by #32

[Bjwebb]

This is fixed for the bullet points that were my original example.

Looks like eval_rst blocks don't internationalize, but I think that's quite different, so I've opened a new issue #47