Add Doc from PEP 727: https://peps.python.org/pep-0727/

[tiangolo]

Add doc and DocInfo from PEP 727: https://peps.python.org/pep-0727/

I'm not too familiar with the process in this codebase and what else would be expected, not sure if I'm missing something else, or if there's anything else I should test, order things in a different way, etc. 🤓

[tiangolo]

Sorry for the lint errors. 🤦

After the first one, I ran the command locally that exposed the error in tests but I didn't realize there was a different one to expose the error in the source. I hope I got them all now. 😅

[tiangolo]

BTW, if you want and/or is easier, feel free to discard this PR and make a new one, or take over and commit on top, etc. It's all good. 😄

[JelleZijlstra]

This should also be documented in the changelog and the documentation page. I'll push some changes in a moment.

[JelleZijlstra]

FYI I pushed documentation, a few more dunder methods, and more tests. (I don't know why people like pickling typing objects but they do, so let's test that it works.)

[AlexWaygood]

I don't know why people like pickling typing objects

though not as much as people like making weakrefs to typing objects, apparently ;)

[JelleZijlstra]

Looks good! (Some concerns about the name of the doc section, but that's something we can always change later.)

[tiangolo]

Thanks @JelleZijlstra! I renamed the section to Annotation metadata as you suggested and @AlexWaygood 👍 -ed.

[tiangolo]

We haven't discussed this anywhere yet, but I just realizing (right after you merged this one 🤦), b now that there's only one class Doc there's probably not a strong argument for having the attribute named documentation, do you think it would be better to name it value?

The main argument I can think of for that is that it's shorter and would be somewhat similar to an enum where the actual value is stored in an attribute value. What do you think?

[JelleZijlstra]

I don't feel too strongly. I think the precise name is nice to make it clear what you are working with (e.g., you can grep for \.documentation more easily than for \.value), and there's some chance we'll add other attributes to the Doc class in the future.

(Just for backward compatibility in typing-extensions, if we do release with .documentation and decide to rename it later, we can preserve compatibility by adding a @property delegating from .documentation to the new name.)

[tiangolo]

Thank you for the quick feedback! Perfect. 🤓🚀