message: fix syntax of gcov exclusion zone.
diff: @@ -547,7 +547,7 @@ Http::Code AdminImpl::handlerHeapProfiler(absl::string_view url, Http::HeaderMap
  // TODO(silentdai) remove the GCOVR when startProfiler is better implemented
  response.add("Fail to start the heap profiler");
  res = Http::Code::InternalServerError;
  - // GCOVR_EXCL_END
  + // GCOVR_EXCL_STOP
  } else {
  response.add("Starting heap profiler");
  res = Http::Code::OK;
  