* upstream/master: (92 commits)
  more formatting (pytorch#8701)
  Fix pytorch#8692 (pytorch#8699)
  Create captured inputs recursively for loop to resolve loop-carried dependencies across nested blocks (pytorch#8345)
  Shard test_nn to reduce runtime for each test target (pytorch#8678)
  Create at::tensor (pytorch#8475)
  Clarify mp note about sharing a tensor's grad field. (pytorch#8688)
  Add owner rule for cpp_extension.py (pytorch#8700)
  fix formatting in :math: in fold docstring (pytorch#8696)
  Some 0-sized dimension support, port catArray away from resizeLegacy. (pytorch#8666)
  Implement flatten function (pytorch#8578)
  Created Tensor::to functions (pytorch#8643)
  Add a warning in gradcheck if inputs precision < float64 (pytorch#8663)
  Fix parsing of floating point defaults in python_arg_parser (pytorch#8681)
  Export ProcessGroupGloo options to Python (pytorch#8664)
  Fix build error in pybind_state_ideep (pytorch#8684)
  Compatibility: write nDimension/_nDimension corresponding to dim()/_dim(). (pytorch#8676)
  Improve win-build.sh for local build (pytorch#8674)
  don't do unnecessary copies for bernoulli_ (pytorch#8682)
  Use parallel if get_num_threads 0 (pytorch#8677)
  Fix serialization for Parameters (pytorch#8633)
  ...

* fix formatting in :math: in fold docstring

* escape more underscores