epub:prefix should not be allowed on embedded svg #1535
Description
While fixing w3c/epub-specs#2555, I noticed epubcheck doesn't report an epub:prefix attribute on an svg element when embedded directly in an html document. The following should be illegal:
<html ... epub:prefix="foo: https://bar.com">
...
<body>
<svg ... epub:prefix="bar: https://foo.com">
...
</svg>
</body>
</html>
The requirement for this is in D.1.4:
Note that for embedded SVG, prefixes MUST be declared on the [html] root html element.
(But this is hardly a priority fix!)