Proposal: Add readMaybe (and possibly readEither) to Prelude, make Haddocks for read more cautionary

[Henning Thielemann]

On Fri, 30 Dec 2016, Andreas Abel wrote:

> When updating the documentation for Read, one can at the same time 
> stress that this class is for parsing values in *Haskell* syntax.  Same 
> for Show, it should be stressed that it is for printing values into 
> their *Haskell* linearization.
>
> I'd guess "Show" is the most abused type class.  (Our own code base, 
> Agda, is a prime example for this.)

my concerns, too