Sphinx has many custom directives and roles, for highlighting and cross referencing docs.

The restructuredtext_lint doesn't support any out of the box (it shouldn't)

So, there are lots of issues coala throws, see coala/documentation#438, regarding the unknown directive and roles

Although it gives support to register roles and directives, it doesn't make sense to register all of them and anything else sphinx adds in the future

Solution: Implement as a setting for sphinx to ignore all unknown directives and roles, through regex