add textarea input to Omnibar widget for hidden inputs

[AlphaBlossom]

I would like to see something like a textarea input added to the Omnibar widget that allows you to enter a hidden input, to pass additional parameters to the results string.

This way we would have the ability to narrow the search results without having to custom code a search widget.

You can see an example of this here https://wordpress.org/plugins/genesis-enews-extended/screenshots/ - a text area labeled: "Hidden Fields:"

Also, if possible it would be nice to have an additional field for the button text.