Concept for function objects that return std::strong_ordering when invoked with two Args.
Declared in <cluster_linearize.h>
template<
typename F,
typename Arg>
concept StrongComparator = std::regular_invocable<F, Arg, Arg> &&
std::is_same_v<std::invoke_result_t<F, Arg, Arg>, std::strong_ordering>;