/// <summary>
 /// 将后面跟有默认行终止符的指定字符串的副本追加到当前 StringBuilder 对象的末尾
 /// </summary>
 /// <param name="sb"></param>
 /// <param name="spaceNum">空格数</param>
 /// <param name="text">要追加的字符串</param>
 /// <returns></returns>
 public static StringBuilder AppendSpaceLine(this StringBuilder sb, int spaceNum, string text)
 {
     sb.Append(StringHelper.Space(spaceNum));
     sb.AppendLine(text);
     return(sb);
 }