fix ocamldoc in Layout
fix ocamldoc in Layout

Reviewed By: evanyeung

Differential Revision: D30279494

fbshipit-source-id: fadaada5eb75cbd0ada99b9c8056d4ab7757cf86

facebook/flow,mroch/flow,mroch/flow,mroch/flow,facebook/flow,mroch/flow,facebook/flow,mroch/flow,mroch/flow,facebook/flow,facebook/flow,facebook/flow,mroch/flow,facebook/flow