Summary:
This PR removes the `.setUseOldBridge(true)` from the documentation. The method was removed from the `ReactInstanceManager` class at [this](1a690d5674 (diff-dc0f3a09c238b372cb1c27aa5f7dcbce)) commit and currently it is not available.
Closes https://github.com/facebook/react-native/pull/10368
Differential Revision: D4016564
Pulled By: JoelMarcey
fbshipit-source-id: 0d9f83c1708dc85043d80a82ecd4fad6b9d42cf5