[presubmit] Enable readability/namespace linter checking.

src/elements.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_H_
 #define V8_ELEMENTS_H_
 
 #include "src/elements-kind.h"
 #include "src/heap/heap.h"
 #include "src/isolate.h"
@@ skipping 171 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(ElementsAccessor);
 };
 
 void CheckArrayAbuse(Handle<JSObject> obj, const char* op, uint32_t index,
                      bool allow_appending = false);
 
 MUST_USE_RESULT MaybeHandle<Object> ArrayConstructInitializeElements(
     Handle<JSArray> array,
     Arguments* args);
 
-} }  // namespace v8::internal
+}  // namespace internal
+}  // namespace v8
 
 #endif  // V8_ELEMENTS_H_