Don't use keg-only and pouring jargon.

This is unnecessarily confusing to end-users and the "fun" naming doesn't really communicate anything. @mistydemeo and I talked about this.

CC @adamv @mistydemeo @jacknagel @tdsmith @asparagui for thoughts and review.
> I therefore take @jacknagel's overall point to be: the new proposal is neither eliminating nor significantly reducing "effort" required by the relevant users; perhaps nothing will do so; the new proposal is thus trading the badness-of-using-a-metaphor for the badness-of-severe-clunkiness; as this trade appears to offer neither significant net improvement or net disimprovement, it doesn't make sense to enact it now. Either it will never be improved upon, in which case, there is no point in doing it at all, or it will be improved upon, in which case there's no point in doing it now.

I couldn't disagree more strongly with this. I've had multiple people complain to me in person when they learn that I work on Homebrew about `keg-only` specifically as an example that they still have no real understanding what it means.