Update mathml-safe-list to mention the new `<a>` element

[lukewarlow]

Ideally the mathml-safe-list document would be updated to mention that MathML Core's new <a> is safe except for when the href contains a javascript: URL.

[polx]

Isn't the <a> element considered an element of html?
It would be easy to actualize however indeed.

[lukewarlow]

https://w3c.github.io/mathml-core/#the-a-element - it's recently been added as a mathml element in its own right, essentially an mrow with an hyperlink behaviour.

[davidcarlisle]

Isn't the <a> element considered an element of html? It would be easy to actualize however indeed.

@polx this is a MathML namespace <a> not an HTML namespace one.