(More) missing instances for Identity and Const

I made a similar (#11210) issue a few months ago and submitted a patch which was accepted. There are some more instances I want to add:

instance Num a => Num (Identity a)
instance Real a => Real (Identity a)
instance Integral a => Integral (Identity a)
instance Fractional a => Fractional (Identity a)
instance Floating a => Floating (Identity a)
instance RealFrac a => RealFrac (Identity a)
instance RealFloat a => RealFloat (Identity a)
instance Bits a => Bits (Identity a)
instance FiniteBits a => FiniteBits (Identity a)
instance IsString => IsString (Identity a)

instance Num a => Num (Const a b)
instance Real a => Real (Const a b)
instance Integral a => Integral (Const a b)
instance Fractional a => Fractional (Const a b)
instance Floating a => Floating (Const a b)
instance RealFrac a => RealFrac (Const a b)
instance RealFloat a => RealFloat (Const a b)
instance Bits a => Bits (Const a b)
instance FiniteBits a => FiniteBits (Const a b)
instance IsString => IsString (Const a b)