* Update babel-types documentation
Mostly just re-run generate-babel-types-docs but also update for some
more validator types.
* Rebuild docs as part of "build-dost"
* Include fields not in BUILDER_KEYS in babel-types docs
These fields don’t have a shorthand for you to pass them to the helper
method, but they are still useful to know about.
* Fields not included in BUILDER_KEYS cannot be "required"
We don’t ever type-check fields not in BUILDER_KEYS so they are never
required.