Socket documentation

[Simon Marlow]

> The function "mkPortNumber" is gone from the Socket library:
> 
>   Prelude> :t Socket.mkPortNumber
> 
>   <interactive>:1: Variable not in scope: `Socket.mkPortNumber'
> 
> Though it is still mentioned in the documentation for
> GHC-5.02.

Sorry about that.  Duly removed.

Cheers,
	Simon