Rename Solutions.py to Solution.py

Author: Tahanima

Algorithms/Easy/206_ReverseLinkedList/Solutions.py renamed to Algorithms/Easy/206_ReverseLinkedList/Solution.py

@@ -8,4 +8,4 @@ def reverseList(self, head: Optional[ListNode]) -> Optional[ListNode]:
             prev = head
             head = next
 
-        return prev
+        return prev