Update skew_heap.py

Author: lighting9999

data_structures/heap/skew_heap.py

@@ -151,7 +151,7 @@ def __iter__(self) -> Iterator[T]:
         [1, 3, 3, 7]
         """
         # Create a temporary heap for iteration
-        temp_heap = SkewHeap()
+        temp_heap: SkewHeap[T] = SkewHeap()
         result: list[T] = []
 
         # Pop all elements from the heap