Sample MentionAtomExtension code throws error rmr0014

[cianmm]

Summary

The sample code linked in the docs for the MentionAtomExtension throws the following error:

You requested an invalid extension from the manager.

'EventsExtension' doesn't exist within this manager. Make sure it is properly added before attempting to use it.

For more information visit https://remirror.io/docs/errors#rmr0014

Steps to reproduce

1. Create a sample React app
2. Create a Remirror Editor by pasting in the sample code from the mention-atom-extension (alternatively use this sandbox)
3. Note the error

Expected results

I expect to see a Remirror Editor which matches the example on the docs page

Actual results

You requested an invalid extension from the manager.

'EventsExtension' doesn't exist within this manager. Make sure it is properly added before attempting to use it.

For more information visit https://remirror.io/docs/errors#rmr0014