Adding a new directive

[sbellem]

Hi, I am wondering whether it would be possible to add a new directive, or to support defining custom directives. The directive I am currently interested in is protocol. I am not sure if that would be welcome, but if yes, I would be happy to help adding it.

[michaelosthege]

I believe this should be covered by https://myst-parser.readthedocs.io/en/latest/syntax/syntax.html#directives-a-block-level-extension-point