Fix return value and type signature of `shell_completion.add_completion_class` function by alexreg · Pull Request #2421 · pallets/click

Hey @alexreg , thank you for responding to my review. I'm glad I was able to introduce you to new concepts.

I've added some small tweaks to your PR, mainly a small refactoring for the fixture, elaboration on the steps of the tests you wrote, and add one more test about using add_completion_class with the name parameter.

Happily merging the PR and hope to see your contributions again in the future!