Summary:Updating the comments to clarify that the selectedIndex prop is not just for pre-selecting an index, but that it can also be used to programmatically change the value of the selected index.
Closes https://github.com/facebook/react-native/pull/6519
Differential Revision: D3075199
Pulled By: mkonicek
fb-gh-sync-id: 8ce336ad491bb2fed13df15ebddb1b24535c50ff
shipit-source-id: 8ce336ad491bb2fed13df15ebddb1b24535c50ff