Apply suggested documentation improvements in useLiveData
Apply suggested documentation improvements in useLiveData

Summary: Applied suggestions by kevinstrider !

Reviewed By: astreet

Differential Revision: D41121602

fbshipit-source-id: 9c08d8f6336c24baa1e805a1735a3fc9ff1f3bf7

facebook/litho,facebook/litho,facebook/litho,facebook/litho,facebook/litho,facebook/litho