message: docs: Update raven-js docs link
diff: raven-node is the official Node.js client for Sentry.
  **Note**: If you're using JavaScript in the browser, you'll need
  -`raven-js <https://github.com/getsentry/raven-js>`_.
  +`raven-js <https://docs.sentry.io/clients/javascript>`_.
  Installation
  ------------
  