Remove superfluous sentence.

index.html

@@ -2627,8 +2627,6 @@ ui.Chapter = Backbone.View.extend({
       data argument and returns an HTML string.  In other words, it conforms to
       the API of Underscore's
       <a href="http://underscorejs.org/#template"><b>template</b></a> function.
-      While this convention is common, it's certainly not required and not used
-      by everyone.
     </p>
 
 <pre>