Add deprecation warning to unsafeCompare

Author: andyarvanitis

src/Data/Ord/Unsafe.purs

@@ -1,8 +1,12 @@
 module Data.Ord.Unsafe (unsafeCompare) where
 
+import Prim.TypeError (class Warn, Text)
 import Data.Ordering (Ordering(..))
 
-unsafeCompare :: forall a. a -> a -> Ordering
+unsafeCompare
+    :: forall a.
+       Warn (Text "'unsafeCompare' is deprecated.")
+    => a -> a -> Ordering
 unsafeCompare = unsafeCompareImpl LT EQ GT
 
 foreign import unsafeCompareImpl