This PR attempts to close #1721

Per the discussion we had around the issue, the potential usability and wcag issues this could cause, there were few pros to relaxing how one could create a grouping of radio buttons.  The issue of how would one name such a group if there is no actual "group" container to name was a very good point.  Though HTML allows for such loose grouping of their radio buttons, they do not have a solution for all the potential a11y problems it can solve.

So, this PR takes a different approach to resolving the issue, and instead adds a note to clarify that a radiogroup does not have to be limited to just radio buttons, while ALSO pointing out the potential UX issues of adding other arbitrary/focusable elements.

Maybe something could even be added to overtly state that "hey if you want to group radio buttons like you can in HTML, then use HTML radio buttons!"

Happy to wordsmith this further (examples might be good?)  Or entertain other solutions (we could close the issue as won't fix, but i recall being told we should do _something_ rather than just that).

I created #2158 as a separate issue to resolve, since a lot of the conversation about this concept touched on the topic now logged in that issue.  and I didn't want resolving this issue/pr to lose that separate though related topic.

Closes #2158