Do not expand PEP-613 type aliases on hover

[hamdanal]

They could become unwieldy especially for large unions. See these two examples

Where the tuple is defined using a type alias in the stub and Where the type of `value` is defines as `Scalar | ListLikeU | None` in pandas-stubs.

In both cases displaying the name of the type alias would make the signature more readable.

[AlexWaygood]

To implement this, we would need to represent PEP-613 aliases as first-class opaque types in our model, similar to what we do with PEP-695 aliases. (That's definitely something we could do, but it's quite different to our current implementation.)

[carljm]

I think this would pretty much require the refactor to split type-expression inference more fully from value-expression inference.