[red-knot] Support unpacking attribute assignments: self.x, self.y = … #15962
Description
The goal of this ticket is to get rid of the TODOs in this test, and support attribute assignments in tuple/list unpackings:
class C:
def __init__(self) -> None:
self.a, self.b = (1, "a")
c_instance = C()
reveal_type(c_instance.a) # should be: Unknown | Literal[1]
reveal_type(c_instance.b) # should be: Unknown | Literal["a"]part of: #14164