Typing spec update for defining "type expression" and other terms

[JelleZijlstra]

Please consider python/typing#1693, also discussed in https://discuss.python.org/t/basic-terminology-for-types-and-type-forms/46741.

This PR defines the terms type expression, annotation expression, type qualifier, and special form and uses them in the spec. The change is intended only to provide more clarity and explicit definitions, so there are no changes to the conformance tests.

• [x] Eric
• [x] Guido
• [x] Jelle
• [x] Rebecca
• [x] Shantanu

[gvanrossum]

Is there somewhere I can view the rendered pages?

[gvanrossum]

(Never mind I just built the html myself. And I sent a review with some nits, I will sign off once you've fixed those.)

[hauntsaninja]

(for future reference, preview is visible at: https://typing--1693.org.readthedocs.build/en/1693/ )

[gvanrossum]

I've signed off on this. Looks great!

[JelleZijlstra]

It's been a week and everyone has signed off, so this change is accepted. I will merge the change.