fix: don't move Sass variables

[aleclarson]

When using postcss-scss syntax, variables are parsed with the decl type, which causes variables to be reordered (which is undesirable).

[Siilwyn]

Hey again, thank you for your contribution! <3

Could you give some more context and explanation, like a 'before' and 'after' CSS code snippet that shows the unwanted behavior and why the variable needs a custom stringifier?

I'm surprised PostCSS doesn't mark declarations as variables, doesn't even differentiate for normal CSS variables like --bg-color: blue;. I think I would also like to add detection for that too but will get into that later.

Btw. this is new behavior so a test should be added, I can do that though. 👍

[Siilwyn]

Small update, I'm planning on dropping support for Node 4 and shifting some things around for version 4. After that I'll pick up this PR for version 4.1! :)

[Siilwyn]

@aleclarson hey could you give an example of the unwanted behavior?

I'm thinking about it and with the current behavior the variables are moved to the top which is usually where you place variables as far as I know, but I feel like I'm missing some context.