message: simplify: Fix assertion for output triangle count
  write is output index count, not output triangle count.
diff: @@ -1426,14 +1426,14 @@ size_t meshopt_simplifySloppy(unsigned int* destination, const unsigned int* ind
  Triangle* tritable = allocator.allocate<Triangle>(tritable_size);
  size_t write = filterTriangles(destination, tritable, tritable_size, indices, index_count, vertex_cells, cell_remap);
  - assert(write <= target_index_count / 3);
  + assert(write <= target_index_count);
  #if TRACE
  printf("duplicates: %d triangles => %d unique\n", unsigned(countTriangles(vertex_cells, indices, index_count)), int(write / 3));
  #endif
  #else
  size_t write = filterTriangles(destination, indices, index_count, vertex_cells, cell_remap);
  - assert(write <= target_index_count / 3);
  + assert(write <= target_index_count);
  #endif
  #if TRACE
  