chore: update comment in DrawerLayoutAndroid (#23730)

Summary:
...referencing stale function component limitations

While preparing a short tutorial on the DrawerLayoutAndroid using the v59 RC, I came across a comment that we can update that states refs as being available only in Class components. This updates that with both class and function components.

If we'd rather delete the comment entirely and move both examples to the website, I'm fine with that too. The current docs page doesn't address the imperative API. https://facebook.github.io/react-native/docs/drawerlayoutandroid

[General] [fixed] - Update stale comment to provide both class and functional component ref example for DrawerLayoutAndroid
Pull Request resolved: https://github.com/facebook/react-native/pull/23730

Differential Revision: D14298527

Pulled By: cpojer

fbshipit-source-id: 3e9f0d6ae49588045fd9d924996fe7cff3d6a156

Libraries/Components/DrawerAndroid/DrawerLayoutAndroid.android.js

@@ -288,7 +288,10 @@ class DrawerLayoutAndroid extends React.Component<Props, State> {
 
   /**
    * Closing and opening example
-   * Note: To access the drawer you have to give it a ref. Refs do not work on stateless components
+   * Note: To access the drawer you have to give it a ref
+   *
+   * Class component:
+   *
    * render () {
    *   this.openDrawer = () => {
    *     this.refs.DRAWER.openDrawer()
@@ -298,9 +301,25 @@ class DrawerLayoutAndroid extends React.Component<Props, State> {
    *   }
    *   return (
    *     <DrawerLayoutAndroid ref={'DRAWER'}>
+   *      {children}
    *     </DrawerLayoutAndroid>
    *   )
    * }
+   *
+   * Function component:
+   *
+   * const drawerRef = useRef()
+   * const openDrawer = () => {
+   *   drawerRef.current.openDrawer()
+   * }
+   * const closeDrawer = () => {
+   *   drawerRef.current.closeDrawer()
+   * }
+   * return (
+   *   <DrawerLayoutAndroid ref={drawerRef}>
+   *     {children}
+   *   </DrawerLayoutAndroid>
+   * )
    */
   _getDrawerLayoutHandle() {
     return ReactNative.findNodeHandle(this._nativeRef.current);