Check for support of std::ranges::subrange(), instead of only header presence
This should fix the build error seen on FreeBSD:
kleopatra-22.12.2/src/dialogs/certificatedetailswidget.cpp:582:78: error: no member named 'subrange' in namespace 'std::ranges' for (const auto uids = key.userIDs(); const auto &uid : std::ranges::subrange(std::next(uids.begin()), uids.end())) { ~~~~~~~~~~~~~^ 1 error generated.