Write docs for IDL properties exposed by WAI-ARIA

[tim-we]

ARIA attributes such as aria-controls have associated properties on the Element interface (e.g. Element.ariaControlsElements). However there are no MDN pages for those properties yet.

Currently Safari is the only browser that has implemented those properties.

Missing pages

• [ ] ElementInternals.ariaActiveDescendantElement
• [ ] ElementInternals.ariaControlsElements
• [ ] ElementInternals.ariaDescribedByElements
• [ ] ElementInternals.ariaDetailsElements
• [ ] ElementInternals.ariaErrorMessageElements
• [ ] ElementInternals.ariaFlowToElements
• [ ] ElementInternals.ariaInvalid
• [ ] ElementInternals.ariaLabelledByElements
• [ ] ElementInternals.ariaOwnsElements
• [ ] Element.role
• [ ] Element.ariaActiveDescendantElement
• [ ] Element.ariaControlsElements
• [ ] Element.ariaDescribedByElements
• [ ] Element.ariaDetailsElements
• [ ] Element.ariaErrorMessageElements
• [ ] Element.ariaFlowToElements
• [ ] Element.ariaInvalid
• [ ] Element.ariaLabelledByElements
• [ ] Element.ariaOwnsElements

It was suggested by @bsmth in the thread of #32327 to create a ticket for this.

[Josh-Cena]

I've added all properties reported as missing from https://dontcallmedom.github.io/mdn-gaps/