fix: restore -h argument

modules/conop/src/chemdict_tool.cc

@@ -77,6 +77,9 @@ int main(int argc, char const *argv[])
       Logger::Instance().PushVerbosityLevel(4);
     } else if (param=="-q") {
       Logger::Instance().PushVerbosityLevel(0);
+    } else if (param=="-h") {
+      PrintUsage();
+      return 0;
     } else {
       std::cout << "Unrecognized argument '" << param << "'" << std::endl;
       std::cout << "Try 'chemdict_tool -h' for more information" << std::endl;