Fix linting.

src/holt59/aoc/2023/day16.py

@@ -56,7 +56,7 @@ def propagate(
         [() for _ in range(len(layout[0]))] for _ in range(len(layout))
     ]
 
-    queue = [(start, direction)]
+    queue: list[tuple[tuple[int, int], Direction]] = [(start, direction)]
 
     while queue:
         (row, col), direction = queue.pop()