reference improvements

[felixroos]

as the standard lib grows, maybe the reference shouldn't be rendered into a single container. I've seen performance issues with that in strudel.

It could be fixed by only showing the tag-filterable list of functions in the docs tab, and open each function inside the same page when clicked. Each function "detail page" can have a back button to return to the function list.
This would also invite adding more detail to each function docs, e.g. adding more than one example or explaining the concepts involved in more detail