Polish code

test=develop

paddle/fluid/operators/sequence_concat_op.cc

@@ -92,6 +92,7 @@ template <typename T>
 using Kernel = op::SeqConcatKernel<paddle::platform::CPUDeviceContext, T>;
 REGISTER_OP_CPU_KERNEL(sequence_concat, Kernel<float>, Kernel<double>,
                        Kernel<int64_t>);
+
 REGISTER_OPERATOR(sequence_concat_grad, paddle::framework::OperatorWithKernel,
                   op::SeqConcatGradShapeInferer);
 template <typename T>