Convert typehints within docstrings to proper in-code typings

[Darylgolden]

Enhancement proposal

Currently, there are many instances of type hints being provided within docstrings - at Paragraph, for example. This has the disadvantage of not being able to be read by IDEs. Since we've standardized all new PRs to use in-code typings since a while back, the old ones should also be changed. A good example of properly implemented typings can be found here, for instance.

This is far too broad an issue to be resolved by a single PR, so I recommend fixing around one file per PR.

Additional comments