Update lazy state documentation
Update lazy state documentation

Summary: Lazy state is now visible in event handlers.

Reviewed By: colriot

Differential Revision: D19534535

fbshipit-source-id: f1d2dbb5eb9f7d6ded3a66fa126da77dffcc753f

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