Create a way to style the invalid messages in native form elements

[Nevraeka]

Given an a form input implements the validation API (Element.validity) we need a way to style the messages. We can use :invalid or :valid to style the actual input in that state but there is no way to style the messages that appear in those states. A part or psuedo selector might be useful here.

I found this image showing different browser implementations here https://webdesign.tutsplus.com/tutorials/html5-form-validation-with-the-pattern-attribute--cms-25145

[github-actions[bot]]

There hasn't been any discussion on this issue for a while, so we're marking it as stale. If you choose to kick off the discussion again, we'll remove the 'stale' label.

[lukewarlow]

Closing as duplicate of https://github.com/openui/open-ui/issues/802