[Book2] Missing semicolon in Listing 68

[LiuZengqiang]

Missing semicolon in Listting 68:

...
        // Change the normal from object space to world space
        auto normal = rec.normal
        normal[0] =  cos_theta*rec.normal[0] + sin_theta*rec.normal[2];
        normal[2] = -sin_theta*rec.normal[0] + cos_theta*rec.normal[2];
...

should be:

...
        // Change the normal from object space to world space
        auto normal = rec.normal;
        normal[0] =  cos_theta*rec.normal[0] + sin_theta*rec.normal[2];
        normal[2] = -sin_theta*rec.normal[0] + cos_theta*rec.normal[2];
...