mypy

46ebacae - stubgen: Replace obsolete typing aliases with builtin containers (#16780)

stubgen: Replace obsolete typing aliases with builtin containers (#16780) Addresses part of #16737 This only replaces typing symbols that have equivalents in the `builtins` module. Replacing other symbols, like those from the `collections.abc` module, are a bit more complicated so I suggest we handle them separately. I also changed the default `TypedDict` module from `typing_extensions` to `typing` as typeshed dropped support for Python 3.7.