Set docs docstring_style (#1343)

Hi, Thank you for this great library!

It seems that the docstrings are not rendered correctly in the docs. I
think we should explicitly set the `docstring_style` because [it
defaults to
`"google"`](https://mkdocstrings.github.io/python/usage/configuration/docstrings/#docstring_style)
but outlines is using numpy.

Before:
![Screenshot 2024-12-16 at 23 00
26](https://github.com/user-attachments/assets/c752ee3d-519e-4098-b943-3aab43c8af25)
After:
![Screenshot 2024-12-16 at 23 00
41](https://github.com/user-attachments/assets/5b5f524b-6921-4dbe-994d-72c079e677bc)


There seem to be other issues in the docstrings:
- for example
[`Properties`](https://github.com/dottxt-ai/outlines/blob/main/outlines/models/openai.py#L23)
should be
[`Attributes`](https://numpydoc.readthedocs.io/en/latest/format.html#parameters)
- only openai and transformers models are present in the [api
reference](https://github.com/dottxt-ai/outlines/blob/main/docs/api/models.md)

I'm happy to make followup PRs for those.

Please let me know if I missed something, I couldn't find related
issues/PRs.

mkdocs.yml

@@ -87,6 +87,7 @@ plugins:
       handlers:
         python:
           options:
+            docstring_style: numpy
             show_submodules: true
   - search
   - section-index