WrappedBifunctor should have an Applicative instance

[treeowl]

instance (Biapplicative p, Monoid a) => Applicative (WrappedBifunctor p a) where
  pure a = WrapBifunctor (bipure mempty a)
  {-# inline pure #-}
  liftA2 f (WrapBifunctor xs) (WrapBifunctor ys) = WrapBifunctor $ biliftA2 mappend f xs ys
  {-# inline liftA2 #-}