This allows for the build to fail if a reference isn't found.

This happens because we have the section kind enabled (needed for examples).

This causes `p` tags which is invalid HTML.

No more Ruby dependency and most important more than 10 times less build time (at least on Windows)!

* Change state field to select
* Include "Choose..." placeholder for select
* Change validated select to .custom-select

instead, only apply outline suppression if the browser wouldn't normally apply the focus outline, using the (currently experimental) `:focus-visible` pseudo-class