swift234

Remove "by" as a dropped preposition (it's still a preposition).

In Cocoa selectors, "by" is often used before an action, i.e.,

  URLByAppendingPathExtension:
  characterRangeByExtendingPosition:inDirection:
  dateByAddingComponents:toDate:options:

Dropping the preposition doesn't make the argument name better.

Swift SVN r15417