[mypy] annotates cls var in other/lfu_cache

Author: spazm

Diff for: other/lfu_cache.py

@@ -281,7 +281,7 @@ def set(self, key: T, value: U) -> None:
 
     @classmethod
     def decorator(
-        cls, size: int = 128
+        cls: type[LFUCache[T, U]], size: int = 128
     ) -> Callable[[Callable[[T], U]], Callable[..., U]]:
         """
         Decorator version of LFU Cache