Button: fix incorrect option name in demo

Author: arschmitz

demos/button/icons.html

@@ -13,7 +13,7 @@
 	$(function() {
 		$( ".widget button:first" ).button({
 			icon: "ui-icon-gear",
-			text: false
+			showLabel: false
 		}).next().button({
 			icon: "ui-icon-triangle-1-w"
 		}).next().button({