docs: Add typehints in both signature and description of API docs (#17815)

This way we can document APIs in methods signature only where they are
checked by the typing system and we get them also in the param
description without having to duplicate in the docstrings (where they
are unchecked).

Twitter: @cbornet_

docs/api_reference/conf.py

@@ -114,8 +114,8 @@ autodoc_pydantic_field_signature_prefix = "param"
 autodoc_member_order = "groupwise"
 autoclass_content = "both"
 autodoc_typehints_format = "short"
+autodoc_typehints = "both"
 
-# autodoc_typehints = "description"
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ["templates"]