SCSS interpreter in attribute lost `$`

[fisker]

require('postcss-selector-parser')(node => console.dir(node.nodes[0].nodes[0].attribute)).processSync('[#{$b}]')

// '#{b}'

#{$b} is expected.

[alexander-akait]

@fisker Yeah, looks like a bug, do you want to send a fix?

[fisker]

I prefer someone more familar with the codebase can fix it.