Controlgroup: Fix quote style in demo

Author: scottgonzalez

demos/controlgroup/toolbar.html

@@ -154,7 +154,7 @@
 			<button id="underline">U</button>
 
 	</div>
-	<pre id="page" contenteditable='true'>
+	<pre id="page" contenteditable="true">
 	The Rime of the Ancient Mariner (text of 1834)
 	BY SAMUEL TAYLOR COLERIDGE
 	Argument