Remove misleading comment about RootTag type not being opaque
Remove misleading comment about RootTag type not being opaque

Summary: Changelog: [Internal]

Reviewed By: lunaleaps

Differential Revision: D40902247

fbshipit-source-id: 5ed8f69bb46e35d5250bd04898765ead500d7db6

facebook/react-native,facebook/react-native,facebook/react-native,facebook/react-native,facebook/react-native,facebook/react-native,facebook/react-native,facebook/react-native,facebook/react-native