Rodrigo Henríquez-Auba

Update statetypes on enumerated_types docs, explain what are statetypes in glossary, and add reference in docstrings of each state_types (differential) to the enumerated_types, and (states) to the glossary.

Preview is broken for now, given the requirements of using other branches of PSY and IS

I'm done with this docs for now @jd-lara @claytonpbarrows