Regenerate all stuff.

grpc/prpc/helloworld_test.pb_test.go

Index: grpc/prpc/helloworld_test.pb_test.go
diff --git a/grpc/prpc/helloworld_test.pb_test.go b/grpc/prpc/helloworld_test.pb_test.go
index 73014b4cb4c05619b23a0113bc643e8aa069931a..19fa20550e98b2e9a641f905676047a39add4b9b 100644
--- a/grpc/prpc/helloworld_test.pb_test.go
+++ b/grpc/prpc/helloworld_test.pb_test.go
@@ -1,6 +1,5 @@
-// Code generated by protoc-gen-go.
+// Code generated by protoc-gen-go. DO NOT EDIT.
 // source: github.com/luci/luci-go/grpc/prpc/helloworld_test.proto
-// DO NOT EDIT!
 
 /*
 Package prpc is a generated protocol buffer package.
@@ -293,7 +292,7 @@ func init() {
 
 var fileDescriptor0 = []byte{
 	// 248 bytes of a gzipped FileDescriptorProto
-	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x09, 0x6e, 0x88, 0x02, 0xff, 0x5c, 0x90, 0x41, 0x4b, 0xc3, 0x30,
+	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0x5c, 0x90, 0x41, 0x4b, 0xc3, 0x30,
 	0x14, 0xc7, 0x57, 0xa9, 0x6e, 0x3e, 0x06, 0x8e, 0x07, 0x4a, 0xd9, 0x69, 0xe4, 0x20, 0x5e, 0xd6,
 	0x42, 0x3d, 0x78, 0x10, 0x4f, 0x3b, 0xe8, 0xc5, 0x4b, 0xfd, 0x00, 0xd2, 0xd5, 0x47, 0x57, 0x78,
 	0x5d, 0x62, 0x92, 0xe2, 0xb2, 0x4f, 0x2f, 0x49, 0x0d, 0xea, 0x2e, 0x8f, 0xfc, 0xdf, 0xff, 0x47,