[presubmit] Enable readability/namespace linter checking.

src/scanner-character-streams.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_SCANNER_CHARACTER_STREAMS_H_
 #define V8_SCANNER_CHARACTER_STREAMS_H_
 
 #include "src/handles.h"
 #include "src/scanner.h"
 #include "src/vector.h"
@@ skipping 165 matching lines @@
   }
   Handle<ExternalTwoByteString> source_;
   const uc16* raw_data_;  // Pointer to the actual array of characters.
 
  private:
   static const size_t kNoBookmark = -1;
 
   size_t bookmark_;
 };
 
-} }  // namespace v8::internal
+}  // namespace internal
+}  // namespace v8
 
 #endif  // V8_SCANNER_CHARACTER_STREAMS_H_