code: public String getSuggestion(MessageId id, String key)
    {
      String messageKey = id.name() + "_SUG." + key;
      String messageDefaultKey = id.name() + "_SUG.default";
      return bundle.containsKey(messageKey) ? getStringFromBundle(messageKey)
          : (bundle.containsKey(messageDefaultKey) ? getStringFromBundle(messageDefaultKey)
              : getSuggestion(id));
    }
docs: Returns the suggestion message for the given message ID and key.
  In other words, for a message ID of `XXX_NNN`, and a key `key`,
  returns the bundle message named `XXX_NNN_SUG.key`.
  If the suggestion key is not found, returns the bundle message
  named `XXX_NNN_SUG.default`.
  If this latter is not found, returns the bundle message nameed
  `XXX_NNN_SUG`.
  
  @param id a message ID
  @param key the key of a specific suggestion string
  @return the associated suggestion string