gui: shorten unknown NAT status to NAT?

tools/chatgui/src/memberlistmodel.cpp

@@ -61,7 +61,7 @@ QVariant MemberListModel::data(const QModelIndex& index, int role) const {
             QString sub;
             if (it->rtt >= 0) sub += QString("rtt=%1ms").arg(it->rtt / 10);
             if (it->natType >= 0) {
-                static const char* nat[] = {"NET","DIR","EIM","DEP","NAT type=UNKNOWN","CONTACT"};
+                static const char* nat[] = {"NET","DIR","EIM","DEP","NAT?","CONTACT"};
                 const char* nt = (it->natType <= 5) ? nat[it->natType] : "?";
                 if (!sub.isEmpty()) sub += " ";
                 sub += nt;