"paint-order" property should apply to the same elements as "fill" and "stroke" properties

[jarek-foksa]

Currently the spec says paint-order can be applied to e.g. <audio> or <image> which doesn't make sense since those elements can't be filled or stroked.

[AmeliaBR]

That makes sense. Probably the result of a blind copy & paste from another property. Should be a straightforward clean-up.

[nikosandronikos]

Yeah it makes sense that paint-order would only apply to the same set that stroke applies to. I'll change it to 'shapes' and 'text content elements'.