Add option for autodoc to show types with class-only (no module prefix)

[gschwaer]

Feature or Bugfix

• Feature

Purpose

• Sometimes modules are used like packages in java, so you can have long redundant module prefixes and the type will be shown in the documentation as a very long string, e.g., Returns: com.mycompany.something.module.MyType.
• This feature PR will add an option to autodoc

  app.add_config_value('autodoc_typehints_types_qualified', 'full', True,
                       ENUM('full', 'class-only'))
  

• By default ("full"), everything stays as it is.
• If "class-only" is used, types are shown in the documentation as __qualname__ and not __module__.__qualname__

  autodoc_typehints_types_qualified = "class-only"
  

• Returns: com.mycompany.something.module.MyType -> Returns: MyType.
• Links continue to work.

Detail

• An example project can be found here.
• This PR needs some input:
  • Is the way it is implemented ok for sphinx? (passing the config from sphinx.ext.autodoc.typehints to sphinx.util.typing)
  • What about the name autodoc_typehints_types_qualified? Is it clear enough?
• TODO
  • A description in the documentation of sphinx.ext.autodoc is still missing.

Relates

• This is a feature that agronholm/sphinx-autodoc-typehints called typehints_fully_qualified. But this extension has some issues and since sphinx.ext.autodoc now supports typehints it is obsolete IMO.

[gschwaer]

I found some other issues with documented types: #9813
I will close this PR until this is discussed.