Deprecating fromIntegral

[Andrew Lelechenko]

> From: Edward Kmett <ekmett at gmail.com>
> 
> fromIntegralMaybe :: (Integral a, Num b) => a -> Maybe b
> fromIntegralMaybe = fromIntegerMaybe . toInteger

I’m late to the party, so might be missing something. Did someone already proposed using http://hackage.haskell.org/package/base-4.14.0.0/docs/Data-Bits.html#v:toIntegralSized, which has a very similar signature?

toIntegralSized :: (Integral a, Integral b, Bits a, Bits b) => a -> Maybe b 

No need for O(n^2) instances and it is already in `base`.

Best regards,
Andrew