update const order (#1770)

codes/codes.go

@@ -19,6 +19,7 @@
 // Package codes defines the canonical error codes used by gRPC. It is
 // consistent across various languages.
 package codes // import "google.golang.org/grpc/codes"
+
 import (
 	"fmt"
 )
@@ -69,10 +70,6 @@ const (
 	// instead for those errors).
 	PermissionDenied Code = 7
 
-	// Unauthenticated indicates the request does not have valid
-	// authentication credentials for the operation.
-	Unauthenticated Code = 16
-
 	// ResourceExhausted indicates some resource has been exhausted, perhaps
 	// a per-user quota, or perhaps the entire file system is out of space.
 	ResourceExhausted Code = 8
@@ -142,6 +139,10 @@ const (
 
 	// DataLoss indicates unrecoverable data loss or corruption.
 	DataLoss Code = 15
+
+	// Unauthenticated indicates the request does not have valid
+	// authentication credentials for the operation.
+	Unauthenticated Code = 16
 )
 
 var strToCode = map[string]Code{