The design of docs is clean and readable Below some constructive feedback:
Why is this useful?
I personally prefer a more authoritative style (instead of a self asked question).
Another good way to write Lwt.bind, that does not use the ppx, is with the >>= operator:
Why would I use this as opposed to the “recommended” PPX?
There seem to be different types of docs on one page (introduction, tutorials / guides, API / reference). I would prefer separate pages for each. The side menu makes it easy to quickly to go to the relevant page.
Apple developer docs might also be an interesting template. They have an intro about the class but do not provide a full tutorial there. They also allow clicking Topics to skip this part.
Elixir follows a similar pattern. They seem to try to keep the intro shortish. Also the side-menu with the functions index helps a lot.
Both have function indexes which help to give a quick overview of what is provided by the module (function names etc.).