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.
 - [Java only] Changing public APIs that take in strings representing phone
   numbers or parts of phone numbers to take in CharSequence instead. Updating
   some of the internal methods to do the same. This affects ShortNumberInfo and
   PhoneNumberUtil, namely the following methods:
   - parse & parseAndKeepRawInput
   - formatWithCarrierCode & formatWithPreferredCarrierCode
   - isNumberMatch
   - isPossibleNumber
   - isAlphaNumber
   - normalizeDigitsOnly & normalizeDiallableCharsOnly