Add newline to the end of Control/Monad/Zip.hs

Fixes problems in some configurations (old versions of cpp?).

Control/Monad/Zip.hs

@@ -50,4 +50,4 @@ class Monad m => MonadZip m where
 instance MonadZip [] where
     mzip     = zip
     mzipWith = zipWith
-    munzip   = unzip
\ No newline at end of file
+    munzip   = unzip