Format imports qualified post

[cblp]

Starting from GHC 8.10, with this extension enabled, one can write:

import A qualified
import B
import C

Now we can save 10 spaces on non-qualified imports!

module Bad where

import Control.Applicative ((<$>))
import System.Directory    (doesFileExist)

import Data.Map            (Map, keys, (!))
import Data.Map            qualified as M

[cblp]

#284 only added support for reading this code, now I want stylish to write it.

[cblp]

Great! Thanks!