Add reference to InputEventJoypadButton in _shortcut_input doc

doc/classes/Node.xml

@@ -100,7 +100,7 @@
 			<return type="void" />
 			<param index="0" name="event" type="InputEvent" />
 			<description>
-				Called when an [InputEventKey] or [InputEventShortcut] hasn't been consumed by [method _input] or any GUI [Control] item. It is called before [method _unhandled_key_input] and [method _unhandled_input]. The input event propagates up through the node tree until a node consumes it.
+				Called when an [InputEventKey], [InputEventShortcut], or [InputEventJoypadButton] hasn't been consumed by [method _input] or any GUI [Control] item. It is called before [method _unhandled_key_input] and [method _unhandled_input]. The input event propagates up through the node tree until a node consumes it.
 				It is only called if shortcut processing is enabled, which is done automatically if this method is overridden, and can be toggled with [method set_process_shortcut_input].
 				To consume the input event and stop it propagating further to other nodes, [method Viewport.set_input_as_handled] can be called.
 				This method can be used to handle shortcuts. For generic GUI events, use [method _input] instead. Gameplay events should usually be handled with either [method _unhandled_input] or [method _unhandled_key_input].