StealthyCoder

Results 2 issues of StealthyCoder

I ran into the following on the [Configure a Registry page](https://docs.docker.com/registry/configuration/). ![Incorrectly rendered](https://user-images.githubusercontent.com/9382530/176183180-53386c07-6eca-4707-b295-16007b1a73de.png) The table was not being rendered correctly and I saw that a caveat about `mediatypes` was missing...

This PR just fixes two small things to make these themes work with GNOME Text Editor version 48.2.