实现悬挂缩进

在项目中需要文本实现word中悬挂缩进样式时，可以仿照下面的方式来做：

- (NSAttributedString *)getAttributeStringWith:(NSString *)str {
   NSDictionary *attributes = @{NSFontAttributeName:FONT_SIZE(12),
                                NSForegroundColorAttributeName:UIColor.normalColor};
   NSMutableAttributedString *mAttr = [[NSMutableAttributedString alloc] initWithString:str attributes:attributes];
   NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
   [paragraphStyle setLineSpacing:6];//行间距
   [paragraphStyle setHeadIndent:8];//悬挂缩进
   [mAttr addAttribute:NSParagraphStyleAttributeName value:paragraphStyle range:NSMakeRange(0, str.length)];
   return mAttr;
}