Merge pull request #21 from purescript/fix-foldable1-identity

Fix Foldable1 Identity instance

Author: hdgarrood

src/Data/Identity.purs

@@ -89,6 +89,8 @@ instance foldableIdentity :: Foldable Identity where
 instance foldable1Identity :: Foldable1 Identity where
   fold1 (Identity x) = x
   foldMap1 f (Identity x) = f x
+  foldl1 _ (Identity x) = x
+  foldr1 _ (Identity x) = x
 
 instance foldableWithIndexIdentity :: FoldableWithIndex Unit Identity where
   foldrWithIndex f z (Identity x) = f unit x z