The URL spec recently changed and the variour "mixins" interfaces are gone,
this commit updates our code and WPT accordingly.
The new expected failures related to HTMLAnchorElement and HTMLAreaElement's
attributes are due to their moving to the HTMLHyperLinkElementUtils interface,
which is not anymore in a separate <script class=untested> element.
Extracted out of #5649
* add more hyperlinks to associated specification for structs/methods
* follow redirects and update links
* replace broken links
* removal of WHATWG multipage page name since the page name is not
guaranteed to be stable
This used to conflict with the util crate from the standard library, which
has long since been removed.
The import in layout has not been changed because of a conflict with the
util mod there.