port to Bikeshed?

[equalsJeffH]

It would be nice to have the various terms used in the doc linked to their definitions, and the author ergonomics for doing this in github-flavored markdown (GFM) are non-existent -- i.e., it is simply "just use brute-force plain HTML" which pretty much sucks. Also linking to sections is easier for author in bikeshed. There's perhaps additional author-ergonomic reasons for maintaining this doc in bikeshed rather than GFM (github flavored markdown), which is what it is written in now.

Tho, if it is ported to bikeshed, then we need to set up the machinery to auto-generate the .html file and publish it as we do e.g. with the webauthn spec.