double clicking callable inlay hint should insert `Callable`, not invalid code

[KotlinIsland]

def f() -> int: ...

a = f

expected

from collections.abc import Callable

def f() -> int: ...

a: Callable[[], int] = f

actual

def f() -> int: ...

a: () -> int = f

Yeah, this is an interesting case. For normal classes we show type[T] because that's a legal annotation (so double clicking it would insert valid type hint but double clicking the constructor signature would not) but for NewType type[N] is not a legal annotation.

Originally posted by @yangdanny97 in #2965

[yangdanny97]

Thanks, one tricky thing to think about is that inserting the annotation might actually create downstream type errors since Callable can't fully model the inferred type.

I guess to be fully accurate we want to make a callable protocol class, but there's no way to do that inline.