docs($anchorScroll): provide an example of basic usage.

Per a request made by Peter Bacon Darwin here:  http://www.benlesh.com/2013/02/angular-js-scrolling-to-element-by-id.html?showComment=1370941217879#c8718313084813008967

Author: benlesh

src/ng/anchorScroll.js

@@ -10,8 +10,36 @@
  * according to rules specified in
  * {@link http://dev.w3.org/html5/spec/Overview.html#the-indicated-part-of-the-document Html5 spec}.
  *
- * It also watches the `$location.hash()` and scroll whenever it changes to match any anchor.
+ * It also watches the `$location.hash()` and scrolls whenever it changes to match any anchor.
  * This can be disabled by calling `$anchorScrollProvider.disableAutoScrolling()`.
+ * 
+ * @example
+   <example>
+     <file name="index.html">
+       <div ng-controller="MainCtrl">
+         <a ng-click="gotoBottom()">Go to bottom</a>
+         <a id="bottom"></a> You're at the bottom!
+       </div>
+     </file>
+     <file name="script.js">
+       function ScrollCtrl($scope, $location, $anchorScroll) {
+         $scope.gotoBottom = function (){
+           // set the location.hash to the id of
+           // the element you wish to scroll to.
+           $location.hash('bottom');
+           
+           // call $anchorScroll()
+           $anchorScroll();
+         }
+       }
+     </file>
+     <file name="style.css">
+       #bottom {
+         display: block;
+         margin-top: 2000px;
+       }
+     </file>
+   </example>
  */
 function $AnchorScrollProvider() {