Merge pull request #22985 from staticdev/master

Initial module docstring for python _pb2_grpc

src/compiler/python_generator.cc

@@ -777,7 +777,9 @@ pair<bool, grpc::string> PrivateGenerator::GetGrpcServices() {
     if (generate_in_pb2_grpc) {
       out->Print(
           "# Generated by the gRPC Python protocol compiler plugin. "
-          "DO NOT EDIT!\n");
+          "DO NOT EDIT!\n\"\"\""
+          "Client and server classes corresponding to protobuf-defined "
+          "services.\"\"\"\n");
       if (!PrintPreamble(out.get())) {
         return make_pair(false, "");
       }