isNaN should be available

[isNaN](http://hackage.haskell.org/package/base-4.12.0.0/docs/Prelude.html#v:isNaN) (and RealFloat) is missing in [Relude.Base](http://hackage.haskell.org/package/relude-0.4.0/docs/Relude-Base.html), while it is present in [Base Prelude](http://hackage.haskell.org/package/relude-0.4.0/docs/Relude-Base.html).

Is there any reason for that ?  How can I fix it ?