Full inlined type hints for thefuzz.process

[mjpieters]

Provides full type hinting for the process module functions.

I have followed the typing best practices where possible, without having to add a dependency on typing_extensions. This
means:

• I inlined the type annotations so they won't be overlooked when making changes to the module. Stub files are great for extension modules, not so great for pure-Python projects.
• To keep compatibility with Python 3.8, I didn't mark the type aliases (_Processor, etc.) with TypeAlias. This isn't necessary anyway as none of the aliases use forward references. The annotations use typing.Union[] and typing.Optional[] instead of the newer | syntax for the same reason.
• Inputs use the most permissable container ABC possible; e.g. contains_dupes only needs to support iteration and length. Return types are the most specific type.

Note that dedupe() explicitly states it can return a list of strings or the original container type.

The types have been verified against the rapidfuzz annotations and sourcecode, with the exception of the query and choice types, which have been constrained here to str. It is possible to extend this to support more types if necessary, but then we'd need to add another typevar and use this in the _Processor and _Scorer type aliases too, which complicates matters. Since all the default processors only accept strings I thought this a good compromise.