Upgrade Prettier to v1.12.1 on fbsource

Summary:
Updates Prettier to v1.12.1, using `xplat/js/scripts/prettier-bump.js` based on the playbook by https://our.intern.facebook.com/intern/wiki/Prettier/upgrade-guide/

All changes related to upgrading or running Prettier

allow-many-files
allow-large-files
bypass-lint
drop-conflicts
ignore-conflict-markers
ignore-signed-source
ignore-nocommit

Reviewed By: benjaffe, ryanmce, yungsters

Differential Revision: D7652946

fbshipit-source-id: 396d45c675e93f2298cd2920d927630c81867447

website/src/components/Playground/URLShortener.js

@@ -49,7 +49,7 @@ export default class URLShortener extends Component<{}, State> {
           window.ga('send', {
             hitType: 'event',
             eventCategory: 'URLShortener',
-            eventAction: 'created'
+            eventAction: 'created',
           });
         }