[BUG] References in TypeAlias are not recognized which act as a str

[Elaina]

Describe the bug

pycln cannot recognize these references in TypeAlias, which brings unexpected "unused" import removed.

To Reproduce

1. Take this code snippet:

   from typing import MutableMapping
   from typing_extensions import TypeAlias
   
   A: TypeAlias = "MutableMapping[str, int]"
   
   def a(x: A) -> int:
       ...
   
   ...# other part of this program

2. Run this Pycln command:

   $ pycln program.py

3. Error traceback or unexpected output (if present):

    program.py:1:0 'from typing import MutableMapping' was removed! 🔮
    program.py 1 import was removed! 🚀
   
    All done! 💪 😎
    1 import was removed, 1 file was changed.

4. Unexpected fixed code (if present):

    from typing_extensions import TypeAlias
   
    A: TypeAlias = "MutableMapping[str, int]"  # pyright reports '"MutableMapping" is not defined'

Expected behavior:

1. Description: pycln won't clear these references in TypeAlias which described as a string.

2. Expected output (if present):

   Looks good! ✨ 🍰 ✨
   1 file left unchanged.

3. Expected fixed code (if present):

   from typing import MutableMapping
   from typing_extensions import TypeAlias
   
   A: TypeAlias = "MutableMapping[str, int]"
   
   def a(x: A) -> int:
       ...
   
   ...# other part of this program

Environment (please complete the following informations):

• Python Version: 3.9.10 in pdm's venv
• Pycln Version: v2.1.2
• OS Type: Windows 10

Additional context

None

[Hadi Alqattan]

Hi @GreyElaina, I've just shipped a PR(#190) that has the fix.

Thanks for reporting the bug.