Amplify Docs are out of sync with AppSync Events Developer Guide

[jeffrey-cochran]

Describe the content issue:
The Amplify docs provide no explanation of the workflow that the AppSync Events docs suggest for integrating with Amplify.

URL page where content issue is:
Linked above: https://docs.amplify.aws/react/build-a-backend/data/subscribe-data/
Linked above: https://docs.aws.amazon.com/appsync/latest/eventapi/build-amplify-app.html