Added all sub sequence type hints [Hacktober Fest] (#3123)

* updating DIRECTORY.md

* chore(all-subsequence): added type hints [HACKTOBER-FEST]

* updating DIRECTORY.md

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

backtracking/all_subsequences.py

@@ -1,3 +1,5 @@
+from typing import Any, List
+
 """
         In this problem, we want to determine all possible subsequences
         of the given sequence. We use backtracking to solve this problem.
@@ -7,11 +9,13 @@
 """
 
 
-def generate_all_subsequences(sequence):
+def generate_all_subsequences(sequence: List[Any]) -> None:
     create_state_space_tree(sequence, [], 0)
 
 
-def create_state_space_tree(sequence, current_subsequence, index):
+def create_state_space_tree(
+    sequence: List[Any], current_subsequence: List[Any], index: int
+) -> None:
     """
     Creates a state space tree to iterate through each branch using DFS.
     We know that each state has exactly two children.