[BUG] string type annotation containing a constant like type

[Hadi Alqattan]

example.py

from ast import Import
from typing import List

def foo(bar: "List['Import']"):
    pass

---

Current behavior, ast.Import is considered as unused:

from typing import List

def foo(bar: "List['Import']"):
    pass

---

Expected behavior, nothing should be changed:

from ast import Import
from typing import List

def foo(bar: "List['Import']"):
    pass