Summary:
We've noticed that many newcomers paste sample code straight into a project created using `react-native init AwesomeProject`, but the sample code assumes the user is creating a new project for each example. This PR makes it so that these samples can be pasted into the same project from the Getting Started.
Closes https://github.com/facebook/react-native/pull/14264
Differential Revision: D5149746
Pulled By: hramos
fbshipit-source-id: cae95ab5b7baf64ddd9fe12d342ad05f785bb381