Expose form repeat child elements in UI

From this feature request:

We have access to the items and children – works great.

It would be nice to see that in the UI now.

For example to use the picker to generate this working code:

formRepeat1.items.sum(`text1.value`)

Right now it has the elements, but not part of the items array…
Screenshot 2023-02-28 at 11.03.29 AM