code: func WrapSyntaxError(r io.Reader, err error) error {
  	if serr, ok := err.(*json.SyntaxError); ok {
  		line, col, _ := errorutil.HighlightBytePosition(r, serr.Offset)
  		return &SyntaxError{serr.Error(), line, col, serr.Offset}
  	}
  
  	return err
  }
docs: // WrapSyntaxError checks whether the given error is a *json.SyntaxError
  // and converts it into a *schema.SyntaxError containing line/col information using the given reader.
  // If the given error is not a *json.SyntaxError it is returned unchanged.