(🎁) Support inferring type from call to `extend` when passed a non-list

[KotlinIsland]

a = []
a.extend([1, 2])
reveal_type(a)  # list[int]

b = []  # error: need type annotation
b.extend((1, 2))
reveal_type(b)  # list[Any]

Mypy should be able to infer the type of b in this case.