Bug with explicit forall in GADTs

[noughtmare]

Input:

{-# LANGUAGE GADTs #-}
{-# LANGUAGE ExplicitForAll #-}

data Some where
  Some :: forall a. a -> Some

Output:

{-# LANGUAGE GADTs #-}
{-# LANGUAGE ExplicitForAll #-}

data Some where
  Some :: a a -> Some

Expected:

{-# LANGUAGE GADTs #-}
{-# LANGUAGE ExplicitForAll #-}

data Some where
  Some :: forall a . a -> Some

$ brittany --version
brittany version 0.13.0.0
Copyright (C) 2016-2019 Lennart Spitzner
Copyright (C) 2019 PRODA LTD
There is NO WARRANTY, to the extent permitted by law.

[tfausak]

I think this is the same as #242. Please re-open if that's not the case!