Pyupgrade to Python 3.9 (#4718)

* Pyupgrade to Python 3.9

* updating DIRECTORY.md

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>

sorts/recursive_insertion_sort.py

@@ -1,11 +1,8 @@
 """
 A recursive implementation of the insertion sort algorithm
 """
-
 from __future__ import annotations
 
-from typing import List
-
 
 def rec_insertion_sort(collection: list, n: int):
     """
@@ -72,6 +69,6 @@ def insert_next(collection: list, index: int):
 
 if __name__ == "__main__":
     numbers = input("Enter integers separated by spaces: ")
-    number_list: List[int] = [int(num) for num in numbers.split()]
+    number_list: list[int] = [int(num) for num in numbers.split()]
     rec_insertion_sort(number_list, len(number_list))
     print(number_list)