fix: remove unused TypeVar from insertion_sort

Author: iosayin

sorts/insertion_sort.py

@@ -14,16 +14,13 @@
 """
 
 from collections.abc import MutableSequence
-from typing import Any, Protocol, TypeVar
+from typing import Any, Protocol
 
 
 class Comparable(Protocol):
     def __lt__(self, other: Any, /) -> bool: ...
 
 
-T = TypeVar("T", bound=Comparable)
-
-
 def insertion_sort[T: Comparable](collection: MutableSequence[T]) -> MutableSequence[T]:
     """A pure Python implementation of the insertion sort algorithm