Add example to compare when referring arguments or not

Author: igrep

examples/strict-gotchas/const.hs

@@ -0,0 +1,10 @@
+dontReferArgs :: a -> a -> a
+dontReferArgs = const
+
+referArgs :: a -> a -> a
+referArgs x _ = x
+
+main :: IO ()
+main = do
+  print $ dontReferArgs "dontReferArgs" undefined
+  print $ referArgs "referArgs" undefined