Document scheduled_event on StageInstance

Author: Middledot

discord/stage_instance.py

@@ -74,6 +74,8 @@ class StageInstance(Hashable):
         The privacy level of the stage instance.
     discoverable_disabled: :class:`bool`
         Whether discoverability for the stage instance is disabled.
+    scheduled_event: Optional[:class:`.ScheduledEvent`]
+        The scheduled event linked with the stage instance, if any.
     """
 
     __slots__ = (