Fix missing namespace comments

PiperOrigin-RevId: 157591364

tensorflow/cc/training/coordinator.cc

@@ -126,4 +126,4 @@ Status Coordinator::ExportCostGraph(CostGraphDef* cost_graph) const {
   return Status::OK();
 }
 
-}  // namespace
+}  // namespace tensorflow

tensorflow/core/common_runtime/memory_types_test.cc

@@ -77,4 +77,4 @@ TEST(MemoryTypeChecker, MemoryTypeForOutput) {
   delete g;
 }
 
-}  // namespace
+}  // namespace tensorflow

tensorflow/core/kernels/hexagon/hexagon_ops_definitions.cc

@@ -398,4 +398,4 @@ GraphTransferInfo::Destination HexagonOpsDefinitions::GetTransferDestination()
     const {
   return GraphTransferInfo::HEXAGON;
 }
-};
+}  // namespace tensorflow

tensorflow/core/lib/io/table_test.cc

@@ -74,7 +74,7 @@ static StringPiece CompressibleString(random::SimplePhilox* rnd,
   dst->resize(len);
   return StringPiece(*dst);
 }
-}
+}  // namespace test
 
 static void Increment(string* key) { key->push_back('\0'); }