Begin: Update signature

Ref qunitjs/qunit#350

entries/QUnit.begin.xml

@@ -3,11 +3,30 @@
 <entry type="method" name="QUnit.begin">
 	<title>QUnit.begin()</title>
 	<signature>
-		<argument name="callback" type="Function">
-			<desc>Callback to execute</desc>
+		<argument name="callback">
+			<desc>Callback to execute. Provides a single argument with the following property:</desc>
+			<type name="Function">
+				<argument name="details" type="Object"/>
+			</type>
+			<property name="totalTests" type="Number">
+				<desc>The number of total tests in the test suite</desc>
+			</property>
 		</argument>
 	</signature>
 	<desc>Register a callback to fire whenever the test suite begins.</desc>
-		<longdesc><code>QUnit.begin()</code> is called once before running any tests.</longdesc>
+	<longdesc>
+		<p>
+			<code>QUnit.begin()</code> is called once before running any tests.
+		</p>
+	</longdesc>
+
+	<example>
+		<desc>Get total amount of tests.</desc>
+		<code><![CDATA[
+QUnit.done(function( details ) {
+	console.log( "Test amount:", details.totalTests );
+});
+]]></code>
+	</example>
 	<category slug="callbacks"/>
 </entry>