Table 12-6, p. 382, "std::get_if<I>(&vt)" should read "std::get_if<i>(&vt)"

[thederz]

Table 12-6, p. 382, "std::get_if<I>(&vt)" should read "std::get_if<i>(&vt)" to match notes provided at right

[JLospinoso]

Thanks, @thederz!