NSAttributedString 和 html 样式（项目符号对齐）

使用NSAttributedString和HTML样式（项目符号对齐）生成文章的案例代码如下：

swift
import UIKit
let htmlString = "
第一段内容
第二段内容
第三段内容
"
let data = Data(htmlString.utf8)
let options: [NSAttributedString.DocumentReadingOptionKey: Any] = [.documentType: NSAttributedString.DocumentType.html, .characterEncoding: String.Encoding.utf8.rawValue]
let attributedString = try? NSAttributedString(data: data, options: options, documentAttributes: nil)
if let attributedString = attributedString {
    let plainText = attributedString.string
    print(plainText)
}