Reconsider structure of docs site

[barryhughes]

I've noticed my browser struggling with the REST API docs which, as I understand it, is essentially one huge page.

The mobile analysis by pagespeed.web.dev shows the worst of the problems, with a pretty massive total blocking time. Here are some of the recommendations for desktop:

Reducing the total DOM size (perhaps, moving away from the one-big-page strategy) would probably solve a great deal. Note also that, for mobile, the main thread work value is a massive 18.2s. Perhaps this resource generally isn't accessed via mobile devices (though I'm not sure about that), but it still serves as a good indicator that the page structure just isn't optimal.