Should it be __cpp_nontype_template_parameter_auto instead of __cpp_nontype_template_parameter_class?

in [ut.hpp](https://github.com/boost-ext/ut/blob/master/include/boost/ut.hpp#L3035)
```cpp
#if defined(__cpp_nontype_template_parameter_class)
template <auto Constant>
#else
template <bool Constant>
#endif
constexpr auto constant = Constant;
```

> https://en.cppreference.com/w/cpp/experimental/feature_test.html