[FR]: Docs for py_venv

[gabrielrussoc]

What is the current behavior?

I was reading the docs for py_venv and they are basically blank. The attributes are **kwargs, without docs.

https://github.com/aspect-build/rules_py/blob/main/docs/venv.md

Describe the feature

It'd be awesome to have more comprehensive docs likes the one we have for py_binary.

[gabrielrussoc]

Huh, this might be on purpose -- I see that py_binary is generating a .venv target under the hood