[presubmit] Enable readability/namespace linter checking.

src/ast-literal-reindexer.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_AST_LITERAL_REINDEXER
 #define V8_AST_LITERAL_REINDEXER
 
 #include "src/ast.h"
 #include "src/scopes.h"
 
@@ skipping 21 matching lines @@
   void UpdateIndex(MaterializedLiteral* literal) {
     literal->literal_index_ = next_index_++;
   }
 
   void Visit(AstNode* node) override { node->Accept(this); }
 
   int next_index_;
 
   DISALLOW_COPY_AND_ASSIGN(AstLiteralReindexer);
 };
-}
-}  // namespace v8::internal
+}  // namespace internal
+}  // namespace v8
 
 #endif  // V8_AST_LITERAL_REINDEXER