[presubmit] Enable readability/namespace linter checking.

src/preparse-data-format.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_PREPARSE_DATA_FORMAT_H_
 #define V8_PREPARSE_DATA_FORMAT_H_
 
 namespace v8 {
 namespace internal {
 
@@ skipping 17 matching lines @@
   static const int kMessageEndPos = 1;
   static const int kMessageArgCountPos = 2;
   static const int kParseErrorTypePos = 3;
   static const int kMessageTemplatePos = 4;
   static const int kMessageArgPos = 5;
 
   static const unsigned char kNumberTerminator = 0x80u;
 };
 
 
-} }  // namespace v8::internal.
+}  // namespace internal
+}  // namespace v8.
 
 #endif  // V8_PREPARSE_DATA_FORMAT_H_