[presubmit] Enable readability/namespace linter checking.

src/preparse-data.h

 // Copyright 2011 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_PREPARSE_DATA_H_
 #define V8_PREPARSE_DATA_H_
 
 #include "src/allocation.h"
 #include "src/hashmap.h"
 #include "src/messages.h"
@@ skipping 188 matching lines @@
 
   Collector<unsigned> function_store_;
   unsigned preamble_[PreparseDataConstants::kHeaderSize];
 
 #ifdef DEBUG
   int prev_start_;
 #endif
 };
 
 
-} }  // namespace v8::internal.
+}  // namespace internal
+}  // namespace v8.
 
 #endif  // V8_PREPARSE_DATA_H_