swift234

[Omit needless words] Split before last preposition in most cases.

Splitting *before* the last preposition tends to keep the
prepositional phrase together. Only leave the preposition on the base
name in rare cases where we would end up with weird argument labels
(e.g., prefer "moveTo(x:y:)" to "move(toX:y:)").

Also, refine our heuristics for when we can remove the preposition
entirely.