message: Link to CONTRIBUTING from JS SDK
  The JS SDK's CONTRIBUTING file is a bit simpler to read. The Synapse version previously used includes mentions of Python lint tools that don't apply here.
diff: Contributing code to The React SDK
  ==================================
  -matrix-react-sdk follows the same pattern as https://github.com/matrix-org/synapse/blob/master/CONTRIBUTING.rst
  +matrix-react-sdk follows the same pattern as https://github.com/matrix-org/matrix-js-sdk/blob/master/CONTRIBUTING.rst
  