UITextView文字距顶显示

默认是居中显示的，想改成距顶显示，其实也就是一句话，写一下，防忘！

//设置文字距顶
    if ([self respondsToSelector:@selector(setAutomaticallyAdjustsScrollViewInsets:)]) {
        self.automaticallyAdjustsScrollViewInsets = NO;
    }