Hello! I am a big fan of pooch! 😄

Would you be interested in my adding type annotations to the library? I think that this can help improve the user experience -- via enhanced 'intellisense' in IDEs when working with pooch, and for instant feedback when a user makes a mistake. I have experience creating/maintaining hydra-zen which makes extensive use of advanced typing features, and I have helped Hypothesis adopt type annotations.

Some things that this would entail:

• Adding typing_extensions as a dependency (this is already quite ubiquitous, and is practically part of the std-lib). This provides backports of nice typing features, such as Literal and Protocol, so that these features can be leveraged without breaking compatibility with older versions of Python.
• Adding both mypy and pyright CI jobs that scan of source and example code, in order to ensure that the annotations are consistent and accurate, and so that they remain this way.

Let me know what you think!