Servo: Implement SVGElement.style

[CYBAI]

Spec: https://drafts.csswg.org/cssom/#dom-elementcssinlinestyle-style

With implementing this, we should be able to fix #26032.

[CYBAI]

Tried to implement style for SVGElement, I found it doesn't fix #26032 and we still can't get style for the create svg circle element :/

const x = document.createElementNS("http://www.w3.org/2000/svg", "circle");
console.log(x.style);

In Gecko, this will log an empty CSS2Properties but it will log undefined in Servo even SVGElement includes ElementCSSInlineStyle.

[jdm]

I have a suspicion that the element returned from createElementNS is a generic Element, rather than an SVGElement. It's worth checking if that is the case.

[CYBAI]

Cool! Yes! It currently returns a generic Element.

https://github.com/servo/servo/blob/3d6fed85ffffcc289a6e0decb0dd70a2985542b0/components/script/dom/create.rs#L111-L114

Before implementing other svg elements, should we return a generic SVGElement here instead?

[jdm]

Yes, that should help.