NSStrikethroughStyleAttributeName

升级ios 10.3后，NSStrikethroughStyleAttributeName属性不管用了，10.3之前的系统都显示正常。
demo如下：
@interface ViewController ()
@property (weak, nonatomic) IBOutlet UILabel *priceLabel;
@end

@implementation ViewController

• (void)viewDidLoad {
  [super viewDidLoad];
  // Do any additional setup after loading the view, typically from a nib.

  NSString *discountPriceStr = @"95";
  NSString *unitStr = @"元";
  NSString *originalPriceStr = @"220";
  NSString *spaceStr = @" ";
  NSString *textStr = [NSString stringWithFormat:@"%@%@%@%@%@", discountPriceStr, unitStr, spaceStr, originalPriceStr, unitStr];
  NSMutableAttributedString *attributeString = [[NSMutableAttributedString alloc] initWithString:textStr];
  [attributeString addAttribute:NSForegroundColorAttributeName value:[UIColor redColor] range:NSMakeRange(0, discountPriceStr.length)];
  [attributeString addAttribute:NSForegroundColorAttributeName value:[UIColor grayColor] range:NSMakeRange(discountPriceStr.length, textStr.length - discountPriceStr.length)];
  [attributeString addAttribute:NSFontAttributeName value:[UIFont systemFontOfSize:10.0f] range:NSMakeRange(0, discountPriceStr.length)];
  [attributeString addAttribute:NSFontAttributeName value:[UIFont systemFontOfSize:8.0f] range:NSMakeRange(discountPriceStr.length, textStr.length - discountPriceStr.length)];
  [attributeString addAttribute:NSStrikethroughStyleAttributeName value:@(NSUnderlineStyleNone) range:NSMakeRange(0, discountPriceStr.length + unitStr.length + spaceStr.length)];
  [attributeString addAttribute:NSStrikethroughStyleAttributeName value:@(NSUnderlinePatternSolid | NSUnderlineStyleSingle) range:NSMakeRange(discountPriceStr.length + unitStr.length + spaceStr.length, originalPriceStr.length + unitStr.length)];
  [attributeString addAttribute:NSStrikethroughColorAttributeName value:[UIColor blackColor] range:NSMakeRange(discountPriceStr.length + unitStr.length + spaceStr.length, originalPriceStr.length + unitStr.length)];
  _priceLabel.attributedText = attributeString;
  }

@end