Consider making more use of Github Pages (e.g. for Rust APIs and spec)

[smolkaj]

Related: #544
Context: #539 (comment)

I wonder if we should make more use of GitHub pages for things like our Rust API (and the spec? though I believe we may already be using gh pages for that?)

cc @fruffy @chrispsommers @jafingerhut

[chrispsommers]

@chreekat Are you going to consider this issue along with your work on #544?

[chreekat]

@chrispsommers I haven't started that other work yet, but I can keep this in mind when I do.