AsyncResult partitions is any AsyncIterator (#202)

* partitions is an AsyncIterator

* fix: import

Author: iamnoah

sqlalchemy-stubs/ext/asyncio/result.pyi

@@ -1,5 +1,5 @@
 from typing import Any
-from typing import Iterator
+from typing import AsyncIterator
 from typing import List
 from typing import Mapping
 from typing import Optional
@@ -32,7 +32,7 @@ class AsyncResult(AsyncCommon):
     ) -> _TAsyncResult: ...
     async def partitions(
         self, size: Optional[int] = ...
-    ) -> Iterator[List[Any]]: ...
+    ) -> AsyncIterator[List[Any]]: ...
     async def fetchone(self) -> Optional[Row]: ...
     async def fetchmany(self, size: Optional[int] = ...) -> List[Row]: ...
     async def all(self) -> List[Row]: ...
@@ -56,7 +56,7 @@ class AsyncScalarResult(AsyncCommon):
     ) -> _TAsyncScalarResult: ...
     async def partitions(
         self, size: Optional[int] = ...
-    ) -> Iterator[List[Any]]: ...
+    ) -> AsyncIterator[List[Any]]: ...
     async def fetchall(self) -> List[Any]: ...
     async def fetchmany(self, size: Optional[int] = ...) -> List[Any]: ...
     async def all(self) -> List[Any]: ...
@@ -77,7 +77,7 @@ class AsyncMappingResult(AsyncCommon):
     ) -> _TAsyncMappingResult: ...
     async def partitions(
         self, size: Optional[int] = ...
-    ) -> Iterator[List[Mapping[Any, Any]]]: ...
+    ) -> AsyncIterator[List[Mapping[Any, Any]]]: ...
     async def fetchall(self) -> List[Mapping[Any, Any]]: ...
     async def fetchone(self) -> Optional[Mapping[Any, Any]]: ...
     async def fetchmany(