Feature request: support Numpy Docstrings fully (e.g. Notes) or google docstring styles

```
/opt/hostedtoolcache/Python/3.10.10/x64/lib/python3.10/site-packages/fastcore/docscrape.py:225: UserWarning: Unknown section Notes
```
Side note: `nbdev` doesn't use `__init__` function docstring in a class if that class has inheritance, rather it uses that base class...

https://google.github.io/styleguide/pyguide.html#38-comments-and-docstrings