Change Show for List to include brackets

src/Prelude.newt

@@ -828,7 +828,7 @@ instance ∀ a b. {{Show a}} {{Show b}} → Show (a × b) where
   show (a,b) = "(" ++ show a ++ ", " ++ show b ++ ")"
 
 instance ∀ a. {{Show a}} → Show (List a) where
-  show xs = joinBy ", " $ map show xs
+  show xs = "[" ++ (joinBy ", " $ map show xs) ++ "]"
 
 -- For now, I'm not having the compiler do this automatically