Make sure no parameter is a list

Signed-off-by: Jan Hamal Dvořák <mordae@anilinux.org>

lib/Hikaru/Types.hs

@@ -114,10 +114,6 @@ where
                       _else -> Nothing
     {-# INLINE fromParam #-}
 
-  instance FromParam String where
-    fromParam = Just . unpack
-    {-# INLINE fromParam #-}
-
   instance FromParam Text where
     fromParam = Just . id
     {-# INLINE fromParam #-}
@@ -213,10 +209,6 @@ where
     toParam char = pack [char]
     {-# INLINE toParam #-}
 
-  instance ToParam String where
-    toParam = pack
-    {-# INLINE toParam #-}
-
   instance ToParam Text where
     toParam = id
     {-# INLINE toParam #-}