Addressing the limitation of get_name

[schaumb]

resolves #151

[schaumb]

I found another way to work "fake object" without requiring C++20 (template variable):

template<class T>
struct X {
   const T value;
   static const X<T> report_if_you_see_link_error_with_this_object; // this is not defined, only declared. equivalent with template varaible
};

template <class T>
constexpr const T& fake_object() noexcept {
    return X<T>::report_if_you_see_link_error_with_this_object.value;
}

This is equivalent to prf::detail::unsafe_declval without the nullptr dereference hack.

I created already the changes. Can I try to apply these modifications too?

What do you think @denzor200 ?

[apolukhin]

Looks very good!

Many thanks for the PR!