[Popup spec] Move invoker activation behaviors to other parts of the HTML spec

[melanierichards]

#355 lands a first editor's draft of <popup> in Open UI, and is intended to be brought to various parts of the HTML spec in WHATWG.

Of the steps in the "Showing/hiding a popup element via the popup attribute" section, @domenic's advice was to:

• Add/modify explicit activation behavior for button and input in the various relevant states. Button element example. Having a single algorithm multiple places call makes sense.
• Modify the focus update steps:

I think the focus update steps need modification for "OR the invoker is an input in the email, number, search, tel, text, or url states and focus is set to the invoker". That is, whenever focus is updated for an input type=email, you need to check if that input type=email is the invoker for a popup and then run these steps if so.

Opening this issue to track the edit as suggested. We can add a snippet to the Open UI spec as I've done here: https://open-ui.org/components/popup#html-incubation-text-user-interaction-focus-processing-model

[github-actions]

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.

[josepharhar]

My HTML spec PR hooks into activation behavior. This issue can be closed