Added comments for Float and Double instances

Author: jchia

src/Data/Binary/Class.hs

@@ -683,13 +683,15 @@ instance (Binary e) => Binary (Seq.Seq e) where
 ------------------------------------------------------------------------
 -- Floating point
 
+-- | Uses non-IEEE754 encoding. Does not round-trip NaN.
 instance Binary Double where
     put d = put (decodeFloat d)
     get   = do
         x <- get
         y <- get
         return $! encodeFloat x y
 
+-- | Uses non-IEEE754 encoding. Does not round-trip NaN.
 instance Binary Float where
     put f = put (decodeFloat f)
     get   =  do