clamp function in base

Hi all, It seems to me that base is missing the very standard function `clamp :: Ord a => a -> a -> a -> a`: ```haskell clamp :: Ord a => a -> a -> a -> a clamp low high = min high .max low ``` I propose it be added to Data.Ord. It's useful, generic, and non-trivial to get right (the "big" number goes with "min" -- causes me cognitive dissonance every time.) Thanks, Sandy