sqlalchemy: Annotate (Async)Session.__(a)enter__ (#7488)

stubs/SQLAlchemy/sqlalchemy/ext/asyncio/session.pyi

@@ -1,3 +1,4 @@
+from _typeshed import Self
 from typing import Any
 
 from ...util import memoized_property
@@ -50,7 +51,7 @@ class AsyncSession(ReversibleProxy):
     async def close(self): ...
     @classmethod
     async def close_all(cls): ...
-    async def __aenter__(self): ...
+    async def __aenter__(self: Self) -> Self: ...
     async def __aexit__(self, type_, value, traceback) -> None: ...
     # proxied from Session
     identity_map: Any

stubs/SQLAlchemy/sqlalchemy/orm/session.pyi

@@ -1,3 +1,4 @@
+from _typeshed import Self
 from collections.abc import Mapping
 from typing import Any, TypeVar, overload
 
@@ -104,7 +105,7 @@ class Session(_SessionClassMethods):
         query_cls: Any | None = ...,
     ) -> None: ...
     connection_callable: Any
-    def __enter__(self): ...
+    def __enter__(self: Self) -> Self: ...
     def __exit__(self, type_, value, traceback) -> None: ...
     @property
     def transaction(self): ...