[presubmit] Enable readability/namespace linter checking.

src/token.h

 // Copyright 2012 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_TOKEN_H_
 #define V8_TOKEN_H_
 
 #include "src/base/logging.h"
 #include "src/globals.h"
 
@@ skipping 300 matching lines @@
     return precedence_[tok];
   }
 
  private:
   static const char* const name_[NUM_TOKENS];
   static const char* const string_[NUM_TOKENS];
   static const int8_t precedence_[NUM_TOKENS];
   static const char token_type[NUM_TOKENS];
 };
 
-} }  // namespace v8::internal
+}  // namespace internal
+}  // namespace v8
 
 #endif  // V8_TOKEN_H_