Keep consistency in example, TL;DR use id as key instead of name

### Are you submitting a **bug report** or a **feature request**?

I'd like to have an example using id as key instead of name, to prevent an error to display close to the wrong field for instance.

### What is the current behavior?

The basic array example is working fine because there is no validation, but if we add validation to this form, it would be buggy as we use "name" as key prop in the loop.

### What is the expected behavior?

We should probaly add a more real worl example with validation and then use a generated id (like Math.random.toString())

### Sandbox Link

### What's your environment?

### Other information

Thank you @erikras