fix(errors): use standard .original rather than .__raw for actual error

lib/instance-validator.js

@@ -403,7 +403,7 @@ class InstanceValidator {
  * @define {string} The error key for arguments as passed by custom validators
  * @define {string} The error key for arguments as passed by custom validators
  * @private
  * @private
  */
  */
-InstanceValidator.RAW_KEY_NAME = '__raw';
+InstanceValidator.RAW_KEY_NAME = 'original';
 
 
 module.exports = InstanceValidator;
 module.exports = InstanceValidator;
 module.exports.InstanceValidator = InstanceValidator;
 module.exports.InstanceValidator = InstanceValidator;