📎 CSS Parser: Add support for the typed `attr` function

[Treycos]

Context

The CSS attr function is currently not fully supported by the Biome parser.

The current Baseline status of this function is somewhat misleading, as it recently evolved to add the <attr-type> parameter.

This syntax is unusual is CSS.

attr(data-size type(<length> | <percentage>), 0px)

Even VSCode struggles to apply syntax highlighting correctly.

Support is gradually being added in all major browsers following interop 2024
https://developer.mozilla.org/en-US/docs/Web/CSS/attr#browser_compatibility
web-platform-tests/interop#521

[dyc3]

This is a bigger task than I thought. Unassigning myself for now.