Annotate yaml configs with comments beside the yaml about docs

[q0rban]

I think this is the JS that's being used: https://github.com/github/docs/blob/774c5d0d9d75f4e62296e1b007c22e4f99010cda/src/content-render/unified/annotate.js#L52

[KeyboardCowboy]

Github Docs is a node module and it's loading annotate.js somewhere in the dependency chain from its package.js file. I don't think that will play very easily with this theme since it's not a node module, but maybe I'm a little out of my tech depth.