genericpath is an internal Python module and shouldn't be imported according to core Python devs. (see [this](https://bugs.python.org/msg358136) comment) (#29903)

For a reason unknown to me, @exxamalte introduced this in https://github.com/home-assistant/home-assistant/pull/14342.

The problem is that Linux and macOS implement `os.path` differently, one imports from [`ntpath.py`](https://github.com/python/cpython/blob/master/Lib/ntpath.py) and the other one from [`posixpath.py`](https://github.com/python/cpython/blob/master/Lib/posixpath.py), and both these files use `genericpath.py`.

Somehow, `isort` on macOS will see `genericpath` as a third party library and sort it accordingly.
Other Unix-based OSes will correctly treat `genericpath` as an internal library.

This problem led to a sorting sequence in the following commits:

- ca0fad2cbb0544125d87d21ffe308cf3addcde5a
- f5d4878992d63683d3da661ef02ae7b51421beb4
- 7d68e88d31246e268db809225e3d924acb1fc352
- 1fee400dcd94229db56a2ada5e3c335aa139146f

This supersedes https://github.com/home-assistant/home-assistant/pull/29893.

tests/components/feedreader/test_init.py

@@ -1,8 +1,8 @@
 """The tests for the feedreader component."""
 from datetime import timedelta
-from genericpath import exists
 from logging import getLogger
 from os import remove
+from os.path import exists
 import time
 import unittest
 from unittest import mock