aria-haspopup does not include all possible values

[andrewseguin]

https://github.com/GoogleChrome/accessibility-developer-tools/blob/master/src/js/Constants.js#L635

Valid values is defined as boolean but actual supported values are "false", "true", "menu", "listbox", "tree", "grid", "dialog".

https://developer.mozilla.org/en-US/docs/Web/API/Element/ariaHasPopup

[crisbeto]

Relevant docs from the W3C https://www.w3.org/TR/wai-aria-1.1/#aria-haspopup.