Add memory_stats() to Redis (#6137)

Author: sobolevn

stubs/redis/redis/client.pyi

@@ -760,6 +760,7 @@ class Redis(Generic[_StrType]):
     def pubsub_numsub(self, *args: _Key) -> list[Tuple[Text, int]]: ...
     def pubsub_numpat(self) -> int: ...
     def monitor(self) -> Monitor: ...
+    def memory_stats(self) -> dict[str, Any]: ...
     def cluster(self, cluster_arg: str, *args: Any) -> Any: ...
     def __enter__(self) -> Redis[_StrType]: ...
     def __exit__(self, exc_type, exc_value, traceback): ...