Add tinygodoc pages

[soypat]

Generating tinygodoc pages and exposing them on the site would be a huge boost to the community. We'd be able to more clearly understand the API layout and cite this in PRs
https://github.com/tinygo-org/tinygodoc

[aykevl]

This looks good. However, we have something similar already: https://tinygo.org/docs/reference/microcontrollers/machine/arduino-uno/
I think these existing pages should either be replaced, or the two should somehow be merged.

[deadprogram]

Whoa, just discovered tinygodoc via this issue... checking it out!