[presubmit] Enable readability/namespace linter checking.

src/accessors.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_ACCESSORS_H_
 #define V8_ACCESSORS_H_
 
 #include "include/v8.h"
 #include "src/allocation.h"
 #include "src/globals.h"
@@ skipping 88 matching lines @@
       Handle<Name> name,
       AccessorNameGetterCallback getter,
       AccessorNameSetterCallback setter,
       PropertyAttributes attributes);
 
   static Handle<ExecutableAccessorInfo> CloneAccessor(
       Isolate* isolate,
       Handle<ExecutableAccessorInfo> accessor);
 };
 
-} }  // namespace v8::internal
+}  // namespace internal
+}  // namespace v8
 
 #endif  // V8_ACCESSORS_H_