Add shoutout to Button and Thumbnail accessories for Section

Author: Rapptz

discord/ui/section.py

@@ -55,7 +55,7 @@ class Section(Item[V]):
     \*children: Union[:class:`str`, :class:`TextDisplay`]
         The text displays of this section. Up to 3.
     accessory: :class:`Item`
-        The section accessory.
+        The section accessory. This is usually either a :class:`Button` or :class:`Thumbnail`.
     id: Optional[:class:`int`]
         The ID of this component. This must be unique across the view.
     """