Author of Material for MkDocs here. MkDocstrings [1] implements automatic generation of reference documentation from sources. It's language-agnostic, actively maintained and currently supports Python [2] and Crystal [3]. It also integrates nicely with Material for MkDocs.
[1]: https://mkdocstrings.github.io/
[2]: https://github.com/mkdocstrings/python
[3]: https://github.com/mkdocstrings/crystal
