Update Linking.js

Reviewed By: svcscm

Differential Revision: D2933128

fb-gh-sync-id: ef33f88db50d6ddb7dd208b7ba5dab41c1ee2f81
shipit-source-id: ef33f88db50d6ddb7dd208b7ba5dab41c1ee2f81

Libraries/Linking/Linking.js

@@ -38,7 +38,7 @@ const DEVICE_NOTIF_EVENT = 'openURL';
  *
  * ```
  * componentDidMount() {
- *   var url = Linking.getInitialURL().then(url) => {
+ *   var url = Linking.getInitialURL().then((url) => {
  *     if (url) {
  *       console.log('Initial url is: ' + url);
  *     }