docs(slideBoxPager): add example with custom ng-click attr

js/angular/directive/slideBoxPager.js

@@ -25,6 +25,18 @@
  * </ion-slide-box>
  * ```
  *
+ * If you provide your own `ng-click` attribute, it overrides the default
+ * click behavior.
+ *
+ * ```html
+ * <ion-slide-box>
+ *   <ion-slide-pager ng-click="doSomething($slideIndex)"></ion-slide-pager>
+ *   <ion-slide>1</ion-slide>
+ *   <ion-slide>2</ion-slide>
+ *   <ion-slide>3</ion-slide>
+ * </ion-slide-box>
+ * ```
+ *
  * @param {expression=} ng-click By default, clicking a pager will select the corresponding
  * slide. You can override this by providing an ng-click expression. The ng-click
  * expression will be provided a `$slideIndex` variable, signifying the slide index