doc: add missing docstrings

[woile]

I'm working in adding some missing documentation to:

• Container
• SolvedDependant
• Dependant
• Dependant
• Marker
• AsyncExecutor

I was wondering if adding mkdocstrings would be welcomed as well. I think having an API Reference at the end of the docs would be useful. Thoughts?

[adriangb]

I've never been able to get mkdocstrings to work well. Let's start with some docstrings and we can add mkdocstrings later.

[woile]

Would you like me to give it a try at mkdocstrings? It's been working well for me.

[adriangb]

Sure worth a shot! It might even uncover some ugly part of the codebase that doesn't play well with it. Thank you for investing time into this.