Clarify namescopes in the presence of nested subgraphs (#1665)
Clarify namescopes in the presence of nested subgraphs (#1665)

* Clarify namescopes in the presence of nested subgraphs

* update checker to handle namescope change

* Update explanation to be consistent with the checker

* undo accidental commits of other files

* undo unintentional changes committed

* undo unintentional changes committed

onnx/onnx,onnx/onnx,onnx/onnx,onnx/onnx