[Bug]: s/S commands are not synonyms of q/Q and are not implemented correctly

[ShukantPal]

I know you're thinking of deprecating this package, but just wanted to report my findings upstream since I took your code.

In section $8.3.6 of the SVG 1.1 specifications, it describes the s/S commands are smooth cubic bezier curves. However, pixi-svg treats them as quadratic bezier curves.

I implemented them here if you need them:

https://github.com/SukantPal/pixi-essentials/blob/eb0c4a91a1b8f47d831e68fdf189ee23e628079b/packages/svg/src/SVGPathNode.ts#L187