message: demo: Fix simplify function
  The previous commit accidentally changed base simplify() to use
  simplifySloppy algorithm.
diff: @@ -368,7 +368,7 @@ void simplify(const Mesh& mesh)
  float target_error = 1e-3f;
  lod.indices.resize(mesh.indices.size());
  - lod.indices.resize(meshopt_simplifySloppy(&lod.indices[0], &mesh.indices[0], mesh.indices.size(), &mesh.vertices[0].px, mesh.vertices.size(), sizeof(Vertex), target_index_count, target_error));
  + lod.indices.resize(meshopt_simplify(&lod.indices[0], &mesh.indices[0], mesh.indices.size(), &mesh.vertices[0].px, mesh.vertices.size(), sizeof(Vertex), target_index_count, target_error));
  lod.vertices.resize(mesh.vertices.size());
  lod.vertices.resize(meshopt_optimizeVertexFetch(&lod.vertices[0], &lod.indices[0], lod.indices.size(), &mesh.vertices[0], mesh.vertices.size(), sizeof(Vertex)));
  