Fix inconsistency

src/main.cpp

@@ -131,7 +131,7 @@ int main(int argc, char* argv[]) {
                 case 'i': changes.emplace(change, arg); break;
                 case 'l': should_list = true; break;
                 case 's': sort = true; break;
-                case '?': throw std::runtime_error("unrecognized option");
+                case '?': throw std::runtime_error {"unrecognized option"};
             }
         }
         if (optind == argc) {