iOS国际化，适配从右到左文字，如阿拉伯文字

NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
paragraphStyle.baseWritingDirection = NSWritingDirectionLeftToRight;//阿拉伯文字会从右到左显示，在这里设置成从左到右显示
paragraphStyle.lineBreakMode = NSLineBreakByCharWrapping;
paragraphStyle.lineSpacing = 6; //设置行间距