PEP 695 (Type Parameter Syntax) tracker - Type aliases

[srittau]

This issue is supposed to track when we can start to use the improved type alias syntax introduced in Python 3.12 (PEP 695 in typeshed. Support is needed in released versions of:

• mypy
• pytype (optional)
• pyright
• PyCharm (optional)

As this is a syntax change, it's unlikely that we can add support before mypy drops support for running under Python 3.11 and below.

Example from the PEP:

type ListOrSet[T] = list[T] | set[T]

[srittau]

Struck pyre (for now) and marked pytype as optional.