[Feature Request] Indicate when a field is used in more than one layout

[benface]

The new Audit tab is great, but it doesn't cover one use case: sometimes I'd like to know at a quick glance which fields are used in multiple layouts.

It could be a simple "tag" next to the field's name, like "Unused", that says "Used X times". Even better would be if it could list all the elements it's used on when hovering the tag or something.

Thank you!