Comment 1 for bug 1426503

So this appears to be a problem with restructuredtext-lint [1]. Since `:linenos:` is a sphinx-specific directive, we either need to update restructuredtext-lint to handle sphinx directives and options /or/ add a specific expression to ignore this particular warning in main (like the default excludes [2]).

[1]: https://github.com/twolfson/restructuredtext-lint

[2]: https://github.com/stackforge/doc8/blob/master/doc8/checks.py#L100..L105