[presubmit] Enable readability/namespace linter checking.

src/heap/incremental-marking-inl.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_HEAP_INCREMENTAL_MARKING_INL_H_
 #define V8_HEAP_INCREMENTAL_MARKING_INL_H_
 
 #include "src/heap/incremental-marking.h"
 #include "src/heap/mark-compact.h"
 
@@ skipping 96 matching lines @@
   }
 
   heap_->mark_compact_collector()->marking_deque()->Unshift(obj);
 }
 
 
 void IncrementalMarking::WhiteToGreyAndPush(HeapObject* obj, MarkBit mark_bit) {
   Marking::WhiteToGrey(mark_bit);
   heap_->mark_compact_collector()->marking_deque()->Push(obj);
 }
-}
-}  // namespace v8::internal
+}  // namespace internal
+}  // namespace v8
 
 #endif  // V8_HEAP_INCREMENTAL_MARKING_INL_H_