[presubmit] Enable readability/namespace linter checking.

src/expression-classifier.h

 // Copyright 2015 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_EXPRESSION_CLASSIFIER_H
 #define V8_EXPRESSION_CLASSIFIER_H
 
 #include "src/messages.h"
 #include "src/scanner.h"
 #include "src/token.h"
@@ skipping 261 matching lines @@
   Error expression_error_;
   Error formal_parameter_initializer_error_;
   Error binding_pattern_error_;
   Error assignment_pattern_error_;
   Error arrow_formal_parameters_error_;
   Error duplicate_formal_parameter_error_;
   Error strict_mode_formal_parameter_error_;
   Error strong_mode_formal_parameter_error_;
   DuplicateFinder* duplicate_finder_;
 };
-}
-}  // v8::internal
+
+}  // namespace internal
+}  // namespace v8
 
 #endif  // V8_EXPRESSION_CLASSIFIER_H