Based type parser

```py
class A:
    a: 1 | 2
based typing.get_annotations(A) # {"a": Union[1, 2]
# such that `1 | 2` == `Union[1, 2]`, not `3`
#  and `A & B` is `basedtyping.Intersection`
```


No idea how this will work with the new type alias syntax in 3.12, maybe we can raise that they should have a `.value` or something.