For example the `Fn.on` in

Input:

instance ordNullable :: (Ord a) => Ord (Nullable a) where
  compare
    = compare `Fn.on` nullableToMaybe

Output:

instance ordNullable :: 
  ( Ord a
  ) =>
  Ord (Nullable a) where
    compare = compare Fn.on nullableToMaybe