Update rat_in_maze.py

Fixes TheAlgorithms#9066
Backtracking/Rat Maze TheAlgorithms#9066

Author: LeTsC0D

Diff for: backtracking/rat_in_maze.py

@@ -116,3 +116,5 @@ def run_maze(maze: list[list[int]], i: int, j: int, solutions: list[list[int]])
     maze = [[0, 1, 0, 1, 1],[0, 0, 0, 0, 0],[1, 0, 1, 0, 1],[0, 0, 1, 0, 0],[1, 0, 0, 1, 0]]
 
     print(solve_maze(maze))
+    import doctest
+    doctest.testmod()