Did a bunch of grepping for `moz*` and searched for "moz" in rustdoc,
deleting anything that looked mozilla-specific. Now there's nothing left
with the "moz" prefix in rustdoc!
I think these might all be from before WebIDL mixins existed. Either way,
multiple inheritance of interfaces that don't have exposed interface objects is
equivalent to mixins.
* Adding in initial support for all HTML*Element interfaces.
* Fix camelcasing of short HTML interface names
* Disabling span test as breaks on taskcluster
