cmd/protoc-gen-go: drop xxx_ prefix for package-level variables

Lower-casing the FileDescriptor variable provides for shorter and
more readable global variable names. This has a very minor benefit
that the read-only data section of a binary is slightly smaller
since function names do end up in the final binary.

Change-Id: I077364905e5c9adea69873b3ea580fddc68b9eb8
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/172119
Reviewed-by: Herbie Ong <herbie@google.com>
diff --git a/internal/testprotos/test/test_weak.pb.go b/internal/testprotos/test/test_weak.pb.go
index 541908c..b36082b 100644
--- a/internal/testprotos/test/test_weak.pb.go
+++ b/internal/testprotos/test/test_weak.pb.go
@@ -30,21 +30,21 @@
 func (*WeakImportMessage) ProtoMessage() {}
 
 func (x *WeakImportMessage) ProtoReflect() protoreflect.Message {
-	return xxx_File_test_test_weak_proto_messageTypes[0].MessageOf(x)
+	return file_test_test_weak_proto_msgTypes[0].MessageOf(x)
 }
 
 func (m *WeakImportMessage) XXX_Methods() *protoiface.Methods {
-	return xxx_File_test_test_weak_proto_messageTypes[0].Methods()
+	return file_test_test_weak_proto_msgTypes[0].Methods()
 }
 
 // Deprecated: Use WeakImportMessage.ProtoReflect.Type instead.
 func (*WeakImportMessage) Descriptor() ([]byte, []int) {
-	return xxx_File_test_test_weak_proto_rawDescGZIP(), []int{0}
+	return file_test_test_weak_proto_rawDescGZIP(), []int{0}
 }
 
 var File_test_test_weak_proto protoreflect.FileDescriptor
 
-var xxx_File_test_test_weak_proto_rawDesc = []byte{
+var file_test_test_weak_proto_rawDesc = []byte{
 	0x0a, 0x14, 0x74, 0x65, 0x73, 0x74, 0x2f, 0x74, 0x65, 0x73, 0x74, 0x5f, 0x77, 0x65, 0x61, 0x6b,
 	0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x12, 0x12, 0x67, 0x6f, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x2e,
 	0x70, 0x72, 0x6f, 0x74, 0x6f, 0x2e, 0x74, 0x65, 0x73, 0x74, 0x22, 0x13, 0x0a, 0x11, 0x57, 0x65,
@@ -56,37 +56,37 @@
 }
 
 var (
-	xxx_File_test_test_weak_proto_rawDesc_once sync.Once
-	xxx_File_test_test_weak_proto_rawDesc_data = xxx_File_test_test_weak_proto_rawDesc
+	file_test_test_weak_proto_rawDescOnce sync.Once
+	file_test_test_weak_proto_rawDescData = file_test_test_weak_proto_rawDesc
 )
 
-func xxx_File_test_test_weak_proto_rawDescGZIP() []byte {
-	xxx_File_test_test_weak_proto_rawDesc_once.Do(func() {
-		xxx_File_test_test_weak_proto_rawDesc_data = protoimpl.X.CompressGZIP(xxx_File_test_test_weak_proto_rawDesc_data)
+func file_test_test_weak_proto_rawDescGZIP() []byte {
+	file_test_test_weak_proto_rawDescOnce.Do(func() {
+		file_test_test_weak_proto_rawDescData = protoimpl.X.CompressGZIP(file_test_test_weak_proto_rawDescData)
 	})
-	return xxx_File_test_test_weak_proto_rawDesc_data
+	return file_test_test_weak_proto_rawDescData
 }
 
-var xxx_File_test_test_weak_proto_messageTypes = make([]protoimpl.MessageType, 1)
-var xxx_File_test_test_weak_proto_goTypes = []interface{}{
+var file_test_test_weak_proto_msgTypes = make([]protoimpl.MessageType, 1)
+var file_test_test_weak_proto_goTypes = []interface{}{
 	(*WeakImportMessage)(nil), // 0: goproto.proto.test.WeakImportMessage
 }
-var xxx_File_test_test_weak_proto_depIdxs = []int32{}
+var file_test_test_weak_proto_depIdxs = []int32{}
 
-func init() { xxx_File_test_test_weak_proto_init() }
-func xxx_File_test_test_weak_proto_init() {
+func init() { file_test_test_weak_proto_init() }
+func file_test_test_weak_proto_init() {
 	if File_test_test_weak_proto != nil {
 		return
 	}
 	File_test_test_weak_proto = protoimpl.FileBuilder{
-		RawDescriptor:      xxx_File_test_test_weak_proto_rawDesc,
-		GoTypes:            xxx_File_test_test_weak_proto_goTypes,
-		DependencyIndexes:  xxx_File_test_test_weak_proto_depIdxs,
-		MessageOutputTypes: xxx_File_test_test_weak_proto_messageTypes,
+		RawDescriptor:      file_test_test_weak_proto_rawDesc,
+		GoTypes:            file_test_test_weak_proto_goTypes,
+		DependencyIndexes:  file_test_test_weak_proto_depIdxs,
+		MessageOutputTypes: file_test_test_weak_proto_msgTypes,
 		FilesRegistry:      protoregistry.GlobalFiles,
 		TypesRegistry:      protoregistry.GlobalTypes,
 	}.Init()
-	xxx_File_test_test_weak_proto_rawDesc = nil
-	xxx_File_test_test_weak_proto_goTypes = nil
-	xxx_File_test_test_weak_proto_depIdxs = nil
+	file_test_test_weak_proto_rawDesc = nil
+	file_test_test_weak_proto_goTypes = nil
+	file_test_test_weak_proto_depIdxs = nil
 }