Alignment doesn't understand QualifiedDo

[scuellar]

haskell mode does not recognize QualifiedDo notation and gets alignment wrong.

The following simple example, from the Qualified Do user guide, should align like

{-# LANGUAGE QualifiedDo #-}
import qualified Some.Module.Monad as M

action :: M.SomeType a
action = M.do x <- u
                   res
                   M.return x

But haskell-mod aligns it as

{-# LANGUAGE QualifiedDo #-}
import qualified Some.Module.Monad as M

action :: M.SomeType a
action = M.do x <- u
                                res
                                M.return x

Probably thinking that M.do is a function, and not special notation.

It currently accepts the following alignment which also parses correctly, but looks ugly.

action :: M.SomeType a
action =
  M.do
  x <- u
  res
  M.return x

Furthermore, since the notation is not recognized, it will get confused with other multi-line notation, like list. Such as in the following example, which Haskell mode will align to configurations that don't parse.

action :: M.SomeType a
action =
  M.do
  x <- u
  fooList
    [  M.do
       res1
    , M.do
      res2
    ]  
  M.return