[WebAPI] Implement dialog toggleevents for dialog open/close

[Rumyra]

Acceptance criteria

• The listed features are documented sufficiently on MDN
• BCD is updated
• Interactive example and data repos are updated if appropriate
• The content has been reviewed as needed

For folks helping with Firefox related documentation

• Set bugs to dev-doc-complete
• Add entry to Firefox release notes for enabled/preview features
• Add/remove entry to Firefox experimental features page for preference/released features

Related Gecko bugs

https://bugzilla.mozilla.org/show_bug.cgi?id=1876762

Other

• Check content open issues to see if any pertain to the subject matter. If there are any that can be closed because of the work, do so. If there are any that can be fixed relatively quickly because of the knowledge from completing this issue and you have time, feel free to go ahead and fix them.

[hamishwillee]

I think this adds beforetoggle and toggle to <dialog> element matching the popover behaviour. The problem is the popover behaviour needs a bit of work - it doesn't mention the events in the docs. I also think the <details> is a little different than documented (it just does the toggle). I am confirming all of this in https://bugzilla.mozilla.org/show_bug.cgi?id=1876762#c14

Status:

• BCD - waiting on BCD team
• Docs (probably):
  • Ff133 dialog toggle beforetoggle events #36606
  • HTMLElement.beforetoggle and toggle - update to mention that beforetoggle is cancellable. This is important
  • Note that details should be the same toggle event AFAIK - not a custom one on HTMLDetailsElement
  • Check the popup docs and dialog docs mention the events in both element and APIs - might need to be "related events"
  • Add a live example?
• Release note
• dev-docs-complete