message: fix style violations
diff: @@ -1531,7 +1531,7 @@ ENOKI_EXPORT void cuda_malloc_trim() {
  std::unordered_multimap<TaggedSize, void *, TaggedSizeHasher> free_map;
  Context &ctx = context();
  - {
  + /* Critical section */ {
  std::lock_guard<std::recursive_mutex> guard(ctx.malloc_mutex);
  free_map.swap(ctx.free_map);
  }
  