Improve form input autocompletion on form playground

[vsgoulart]

What should we do?

On #1356 we already fixed an improved the autocompletion but we can still improve it even further as mentioned here.
Possible improvements:

• When applying an autocomplete suggestion inside quotes for a property name we can append a colon and comma on the same line
• We can the autocompletion schema aware, meaning for fields that are bound to specific field we can auto-suggest a JSON value in the specific format that form element expects. For example: for options we could suggest an object with label and value fields

Why should we do it?

To improve our UX

[vsgoulart]

Another suggestion was made here