Proposal #3339: Add (+>) as a synonym for mappend

[Yitzchak Gale]

Thomas Schilling wrote:
> So, NOTHING would break if you made made SemiGroup a superclass of Monoid?

Right, I didn't propose that. Really, in hindsight, it should be. But
as you say,
it would break things. Sorry if I was not clear.

Rather, each library author should add the superclass.

Unfortunately, this is similar to the situation with Functor and
Monad.

Thanks,
Yitz