Firefox: floated images wrapped in links - missing resize handles

[indigoxela]

If an image is wrapped in a link and also floated (left / right), the editor's image resize handles hardly ever show up.

Sort of a follow-up to #56, which solved a similar problem with images not wrapped in links.
Seems like the browser's a bit "opinionated" re that combo. 🦊

[indigoxela]

BTW, this is also sort of a follow-up to #125, as there's also a problem with button active state in such cases.

The last time I looked at the problem has() didn't have full support in FF, yet. But now there is. So there might be a small CSS-only solution.