Code changes:
 - Added isSmsServiceForRegion(PhoneNumber, RegionCode) API in C++ and Java
   short number info libraries. An SMS service is where the primary or only
   intended usage is to receive and/or send text messages (SMSs). This includes
   MMS as MMS numbers downgrade to SMS if the other party isn't MMS-capable. The
   is_sms_service metadata is also serialized for the first time.  JS is not
   affected because it doesn't have short numbers.
 - Documentation update for private variables VALID_PUNCTUATION and
   SINGLE_INTERNATIONAL_PREFIX, also renaming the latter from
   UNIQUE_INTERNATIONAL_PREFIX.