Document that Button doesn't interpret touch input (= no multitouch)

TouchScreenButton should be used for gameplay actions instead.

(cherry picked from commit f6087d3f2b3073e00657ab87a5760fcd29974f6e)

doc/classes/Button.xml

@@ -18,6 +18,7 @@
 		[/codeblock]
 		Buttons (like all Control nodes) can also be created in the editor, but some situations may require creating them from code.
 		See also [BaseButton] which contains common properties and methods associated with this node.
+		[b]Note:[/b] Buttons do not interpret touch input and therefore don't support multitouch, since mouse emulation can only press one button at a given time. Use [TouchScreenButton] for buttons that trigger gameplay movement or actions, as [TouchScreenButton] supports multitouch.
 	</description>
 	<tutorials>
 		<link title="2D Dodge The Creeps Demo">https://godotengine.org/asset-library/asset/515</link>

doc/classes/TouchScreenButton.xml

@@ -4,7 +4,7 @@
 		Button for touch screen devices for gameplay use.
 	</brief_description>
 	<description>
-		TouchScreenButton allows you to create on-screen buttons for touch devices. It's intended for gameplay use, such as a unit you have to touch to move.
+		TouchScreenButton allows you to create on-screen buttons for touch devices. It's intended for gameplay use, such as a unit you have to touch to move. Unlike [Button], TouchScreenButton supports multitouch out of the box. Several TouchScreenButtons can be pressed at the same time with touch input.
 		This node inherits from [Node2D]. Unlike with [Control] nodes, you cannot set anchors on it. If you want to create menus or user interfaces, you may want to use [Button] nodes instead. To make button nodes react to touch events, you can enable the Emulate Mouse option in the Project Settings.
 		You can configure TouchScreenButton to be visible only on touch devices, helping you develop your game both for desktop and mobile devices.
 	</description>