Description of the change

This PR changes the types of traverseArrayImpl to be more true to how they are actually used.

This changes traverseArrayImpl from

traverseArrayImpl
  :: forall m a b
   . (m (a -> b) -> m a -> m b)
  -> ((a -> b) -> m a -> m b)
  -> (a -> m a)
  -> (a -> m b)
  -> Array a
  -> m (Array b)

to

traverseArrayImpl
  :: forall m a b
   . (forall x y. m (x -> y) -> m x -> m y)
  -> (forall x y. (x -> y) -> m x -> m y)
  -> (forall x. x -> m x)
  -> (a -> m b)
  -> Array a
  -> m (Array b)

traverseArrayImpl is called like the following:

instance traversableArray :: Traversable Array where
   traverse = traverseArrayImpl apply map pure  

Here the apply, map, and pure functions are all polymorphic in their arguments (the x and y in the changed type above), so this new type for traverseArrayImpl is more true.

Also, in the FFI files for traverseArrayImpl, apply, map, and pure are used as if they are polymorphic. For instance, pure is used on an Array, not an a:

Checklist:

• Added the change to the changelog's "Unreleased" section with a reference to this PR (e.g. "- Made a change (#0000)")
• Linked any existing issues or proposals that this pull request should close
• Updated or added relevant documentation
• Added a test for the contribution (if applicable)