stdlib/NSString APIs on String: change stringByAppendingPathExtension() to return an optional String.  This behavior is not documeted, though.
stdlib/NSString APIs on String: change stringByAppendingPathExtension() to
return an optional String.  This behavior is not documeted, though.


Swift SVN r21016

apple/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation