Allow usage of all `typing` members in annotations

```py
def foo() -> Never: ...  # allowed
b = Union[int, str]  # not allowed
```
`basedtyping` as well.
Maybe `types` as well.

We could modify `sitecustomize.py` to actually load these for real. (`mypy install-site-types` maybe)

```py
b = Union[int, str]  # allowed
```