CSS Modules: Respect print width when composing multiple classes

This https://github.com/prettier/prettier/pull/2190 is great work, but composes can also accept multiple classes.

For example the following block:

.thumbnailText {
  composes:
    global(c-silver)
    global(lineHeight-s)
    global(breadkPointM-lineHeight-m)
    global(breakPointL-lineHeight-l)
    global(fontSize-xs)
    global(breakPointM-fontSize-s)
    global(breakPointL-fontSize-m);
}

is formatted to:

.thumbnailText {
  composes: global(c-silver) global(lineHeight-s) global(breadkPointM-lineHeight-m) global(breakPointL-lineHeight-l) global(fontSize-xs) global(breakPointM-fontSize-s) global(breakPointL-fontSize-m);
}

(prettier@1.5.2)

It would be nice have one class per line, or respect the print width.

What do you think? I'm happy to create a PR if you'd like 😄

Start by reviewing the linked Prettier pull request #2190 and the existing CSS formatting behavior for multi-class composes declarations. The work is done when multiple composed classes are broken across lines according to the configured print width, rather than being emitted as one long line.