[presubmit] Enable readability/namespace linter checking.

src/heap/spaces-inl.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_HEAP_SPACES_INL_H_
 #define V8_HEAP_SPACES_INL_H_
 
 #include "src/heap/spaces.h"
 #include "src/isolate.h"
 #include "src/msan.h"
@@ skipping 469 matching lines @@
 LargePage* LargePage::Initialize(Heap* heap, MemoryChunk* chunk) {
   heap->incremental_marking()->SetOldSpacePageFlags(chunk);
   return static_cast<LargePage*>(chunk);
 }
 
 
 intptr_t LargeObjectSpace::Available() {
   return ObjectSizeFor(heap()->isolate()->memory_allocator()->Available());
 }
 
-}
-}  // namespace v8::internal
+}  // namespace internal
+}  // namespace v8
 
 #endif  // V8_HEAP_SPACES_INL_H_