Method log_contexts

test/doctest.h:5453–5464

                , opt(co) {}

        void log_contexts() {
            int num_contexts = get_num_active_contexts();
            if(num_contexts) {
                auto              contexts = get_active_contexts();
                std::stringstream ss;
                for(int i = 0; i < num_contexts; ++i) {
                    contexts[i]->stringify(&ss);
                    xml.scopedElement("Info").writeText(ss.str());
                    ss.str("");
                }
            }
        }

        unsigned line(unsigned l) const { return opt.no_line_numbers ? 0 : l; }