Update examples.
Add docstrings.
Push more stuff into sphinx literal includes.

It did require some contortions, but I think this is better? It's definitely
more maintainable than line numbers. At worst I can add more # begin whatever
blocks.
Pass the parser along because of reasons.

Specifically, it's convenient to pull the factory off of the parser. Who knows;
maybe someone will need it for other reasons.
Update examples again.
Update the docs too.