groupValue Documentation a bit confusing

[Benjy1979]

The readme.md says

groupValue | any | the value representing a radio group's current value. supply the same groupValue to every radio-button in a group

I'm not sure what this means. It sounds like you send what would normally be "name" (to make them act as a radio group) but then fetch groupValue to get the currently selected value?
Can more documentation be put in to explain how you fetch the selected value?

[lukemelia]

This addon follows a data-down, actions-up approach, so you pass the current value of the radio button group into each button as groupValue and receive the changed action when a radio button is changing value by virtue of someone clicking it.

I'm happy to accept a PR that improves the documentation.