Migrate documentation to ... something?

[mpounsett]

[mpounsett]

Since originally opening this issue, MkDocs has done unmaintained. The 2.0 replacement will not support plugins, and a number of the requirements of this project's documentation depend on a plugin system (e.g. mkdocstrings). Zeniscal looks like a promising alternative already, but the mkdocstrings implementation is still preliminary and probably not ready for production use.

Putting this issue on hold for now (which may not look like a change, but I really was getting to it ... really. 😁 ).