add missing KeyboardAvoidingView documentation

Summary: Closes https://github.com/facebook/react-native/pull/9667

Differential Revision: D3791743

Pulled By: hramos

fbshipit-source-id: 823bf44028d8fb01f13510753362b8da3692f936

Libraries/Components/Keyboard/KeyboardAvoidingView.js

@@ -47,6 +47,10 @@ type LayoutEvent = {
 
 const viewRef = 'VIEW';
 
+/**
+ * It is a component to solve the common problem of views that need to move out of the way of the virtual keyboard.
+ * It can automatically adjust either its position or bottom padding based on the position of the keyboard.
+ */
 const KeyboardAvoidingView = React.createClass({
   mixins: [TimerMixin],
 

website/server/extractDocs.js

@@ -489,6 +489,7 @@ const components = [
   '../Libraries/Components/DatePicker/DatePickerIOS.ios.js',
   '../Libraries/Components/DrawerAndroid/DrawerLayoutAndroid.android.js',
   '../Libraries/Image/Image.ios.js',
+  '../Libraries/Components/Keyboard/KeyboardAvoidingView.js',
   '../Libraries/CustomComponents/ListView/ListView.js',
   '../Libraries/Components/MapView/MapView.js',
   '../Libraries/Modal/Modal.js',