update docs for TabController PageCarousel

Author: ethanshar

src/components/tabController/PageCarousel.js

@@ -9,6 +9,7 @@ const {Code, block, call} = Animated;
 /**
  * @description: TabController's Page Carousel
  * @example: https://github.com/wix/react-native-ui-lib/blob/master/demo/src/screens/componentScreens/TabControllerScreen/index.js
+ * @notes: You must pass `asCarousel` flag to TabController and render your TabPages inside a PageCarousel
  */
 class PageCarousel extends PureComponent {
   static displayName = 'TabController.PageCarousel';