[docs][1.5] update RPC docs to reflect correct use of dist_autograd backwards and dist_optim step()

[rohan-varma]

• Clarify that torch.distributed.autograd.backwards() does not use the current thread local autograd context, instead it looks it up based on the context_id passed in
• Clarify the same for torch.distributeed.optimizer.optim.step()

[osalpekar]

LGTM!

[facebook-github-bot]

@rohan-varma has imported this pull request. If you are a Facebook employee, you can view this diff on Phabricator.

[dr-ci]

💊 CircleCI build failures summary and remediations

As of commit 9f9b75d (more details on the Dr. CI page):

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✅ None of the build failures appear to be your fault 💚

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• 1/1 broken upstream at merge base 90ca7a1 since Mar 12

  Please rebase on the viable/strict branch (expand for instructions)

  If your commit is newer than viable/strict, you can try basing on an older, stable commit:

  git fetch origin viable/strict
  git rebase --onto viable/strict $(git merge-base origin/master HEAD)
  

  If your commit is older than viable/strict:

  git fetch origin viable/strict
  git rebase viable/strict
  

  Check out the recency history of this "viable master" tracking branch.

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🚧 1 upstream failure:

These were probably caused by upstream breakages:

• caffe2_onnx_ort2_py3_6_clang7_ubuntu16_04_test since Mar 12

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This comment has been revised 4 times.

[facebook-github-bot]

@rohan-varma has imported this pull request. If you are a Facebook employee, you can view this diff on Phabricator.

[facebook-github-bot]

@rohan-varma merged this pull request in f933fa3.