codegen: Correct indentation (#26702)

src/compiler/cpp_generator.cc

@@ -1365,7 +1365,7 @@ void PrintHeaderService(grpc_generator::Printer* printer,
   }
   PrintHeaderClientMethodCallbackInterfacesEnd(printer, vars);
   printer->Outdent();
-  printer->Print("private:\n");
+  printer->Print(" private:\n");
   printer->Indent();
   for (int i = 0; i < service->method_count(); ++i) {
     PrintHeaderClientMethodInterfaces(printer, service->method(i).get(), vars,

test/cpp/codegen/compiler_test_golden

@@ -129,7 +129,7 @@ class ServiceA final {
     typedef class async_interface experimental_async_interface;
     virtual class async_interface* async() { return nullptr; }
     class async_interface* experimental_async() { return async(); }
-  private:
+   private:
     virtual ::grpc::ClientAsyncResponseReaderInterface< ::grpc::testing::Response>* AsyncMethodA1Raw(::grpc::ClientContext* context, const ::grpc::testing::Request& request, ::grpc::CompletionQueue* cq) = 0;
     virtual ::grpc::ClientAsyncResponseReaderInterface< ::grpc::testing::Response>* PrepareAsyncMethodA1Raw(::grpc::ClientContext* context, const ::grpc::testing::Request& request, ::grpc::CompletionQueue* cq) = 0;
     virtual ::grpc::ClientWriterInterface< ::grpc::testing::Request>* MethodA2Raw(::grpc::ClientContext* context, ::grpc::testing::Response* response) = 0;
@@ -738,7 +738,7 @@ class ServiceB final {
     typedef class async_interface experimental_async_interface;
     virtual class async_interface* async() { return nullptr; }
     class async_interface* experimental_async() { return async(); }
-  private:
+   private:
     virtual ::grpc::ClientAsyncResponseReaderInterface< ::grpc::testing::Response>* AsyncMethodB1Raw(::grpc::ClientContext* context, const ::grpc::testing::Request& request, ::grpc::CompletionQueue* cq) = 0;
     virtual ::grpc::ClientAsyncResponseReaderInterface< ::grpc::testing::Response>* PrepareAsyncMethodB1Raw(::grpc::ClientContext* context, const ::grpc::testing::Request& request, ::grpc::CompletionQueue* cq) = 0;
   };