[presubmit] Enable readability/namespace linter checking.

src/unique.h

 // Copyright 2013 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_UNIQUE_H_
 #define V8_UNIQUE_H_
 
 #include <ostream>  // NOLINT(readability/streams)
 
 #include "src/base/functional.h"
@@ skipping 337 matching lines @@
       Unique<T>* new_array = zone->NewArray<Unique<T> >(new_capacity);
       if (size_ > 0) {
         memcpy(new_array, array_, size_ * sizeof(Unique<T>));
       }
       capacity_ = new_capacity;
       array_ = new_array;
     }
   }
 };
 
-} }  // namespace v8::internal
+}  // namespace internal
+}  // namespace v8
 
 #endif  // V8_UNIQUE_H_