Fix React Native docs
Fix React Native docs

Summary: Reckon this broke with the Docusaurus 2 upgrade.

Reviewed By: mweststrate

Differential Revision: D24537442

fbshipit-source-id: b3fbac990f82819941e17f0f7ce89df616aa6718

facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper