DataStore `Manipulating Data` code example is broken

[david-mcafee]

Describe the content issue:
A clear and concise description of what the content issue is. Is there content missing or is there incorrect content?
The code example from the listed docs page does not work when attempting to input data into the input field, resulting in a The source object is not a valid model error. This is because a record was never first created, and copyOf expects a valid model (not undefined).

URL page where content issue is:
https://docs.amplify.aws/lib/datastore/data-access/q/platform/js/#create-and-update

[renebrandel]

Issue is addressed by initial PR.