[presubmit] Enable readability/namespace linter checking.

src/elements-kind.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_ELEMENTS_KIND_H_
 #define V8_ELEMENTS_KIND_H_
 
 #include "src/base/macros.h"
 #include "src/checks.h"
 
@@ skipping 208 matching lines @@
   return from_kind;
 }
 
 
 inline bool IsTransitionableFastElementsKind(ElementsKind from_kind) {
   return IsFastElementsKind(from_kind) &&
       from_kind != TERMINAL_FAST_ELEMENTS_KIND;
 }
 
 
-} }  // namespace v8::internal
+}  // namespace internal
+}  // namespace v8
 
 #endif  // V8_ELEMENTS_KIND_H_