Add sqlalchemy.orm.with_expression function alias (#101)

Author: isra17

sqlalchemy-stubs/orm/__init__.pyi

@@ -70,6 +70,7 @@ contains_eager: Any = ...
 defer: Any = ...
 undefer: Any = ...
 undefer_group: Any = ...
+with_expression: Any = ...
 load_only: Any = ...
 lazyload: Any = ...
 lazyload_all: Any = ...