Update docs for master to remove Python 2 references

[jlin27]

Full details in task: https://our.internmc.facebook.com/intern/tasks/?t=64776265

With pytroch 1.5+ we remove python2 support from PyTorch. All documentation under docs/ and on the pytorch.org website needs to remove Python 2 references.

[dr-ci]

💊 CircleCI build failures summary and remediations

As of commit d8e3ffa (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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• 4/4 broken upstream at merge base 3da67ce on Apr 06 from 2:27pm to 6:52pm PDT (15 commits; 8ef82fc - 4c14005)

  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 https://github.com/pytorch/pytorch viable/strict
  git rebase --onto FETCH_HEAD $(git merge-base origin/master HEAD)
  

  If your commit is older than viable/strict:

  git fetch https://github.com/pytorch/pytorch viable/strict
  git rebase FETCH_HEAD
  

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

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🚧 4 upstream failures:

These were probably caused by upstream breakages:

• caffe2_onnx_main_py3_6_clang7_ubuntu16_04_test on Apr 06 from 2:27pm to 6:52pm PDT (15 commits; 8ef82fc - 4c14005)
• caffe2_onnx_ort2_py3_6_clang7_ubuntu16_04_test on Apr 06 from 2:27pm to 7:37pm PDT (18 commits; 8ef82fc - 459163b)
• caffe2_onnx_ort1_py3_6_clang7_ubuntu16_04_test on Apr 06 from 2:27pm to 7:37pm PDT (18 commits; 8ef82fc - 459163b)
• pytorch_windows_vs2019_py36_cuda10.1_test1 on Apr 06 from 2:27pm to 7:37pm PDT (18 commits; 8ef82fc - 459163b)

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This comment has been revised 6 times.

[orionr]

Thank you!

[facebook-github-bot]

@jlin27 is landing this pull request. If you are a Facebook employee, you can view this diff on Phabricator.

[facebook-github-bot]

@jlin27 merged this pull request in 43234be.

[ezyang]

There appear to be syntax errors in this change

Apr 08 19:03:13 File "jit_language_reference.rst", line 1701, in default
Apr 08 19:03:13 Failed example:
Apr 08 19:03:13     from typing import List, Dict
Apr 08 19:03:13 
Apr 08 19:03:13     class Foo(nn.Module):
Apr 08 19:03:13         # `words` is initialized as an empty list, so its type must be specified
Apr 08 19:03:13         words: List[str]
Apr 08 19:03:13 
Apr 08 19:03:13         # The type could potentially be inferred if `a_dict` (below) was not
Apr 08 19:03:13         # empty, but this annotation ensures `some_dict` will be made into the
Apr 08 19:03:13         # proper type
Apr 08 19:03:13         some_dict: Dict[str, int]
Apr 08 19:03:13 
Apr 08 19:03:13         def __init__(self, a_dict):
Apr 08 19:03:13             super(Foo, self).__init__()
Apr 08 19:03:13             self.words = []
Apr 08 19:03:13             self.some_dict = a_dict
Apr 08 19:03:13 
Apr 08 19:03:13             # `int`s can be inferred
Apr 08 19:03:13             self.my_int = 10
Apr 08 19:03:13 
Apr 08 19:03:13         def forward(self, input):
Apr 08 19:03:13             # type: (str) -> int
Apr 08 19:03:13             self.words.append(input)
Apr 08 19:03:13             return self.some_dict[input] + self.my_int
Apr 08 19:03:13 
Apr 08 19:03:13     f = torch.jit.script(Foo({'hi': 2}))
Apr 08 19:03:13 
Apr 08 19:03:13 
Apr 08 19:03:13 
Apr 08 19:03:13     .. testcode::
Apr 08 19:03:13 
Apr 08 19:03:13         from typing import List, Dict
Apr 08 19:03:13 
Apr 08 19:03:13         class Foo(nn.Module):
Apr 08 19:03:13             __annotations__ = {'words': List[str], 'some_dict': Dict[str, int]}
Apr 08 19:03:13 
Apr 08 19:03:13             def __init__(self, a_dict):
Apr 08 19:03:13                 super(Foo, self).__init__()
Apr 08 19:03:13                 self.words = []
Apr 08 19:03:13                 self.some_dict = a_dict
Apr 08 19:03:13 
Apr 08 19:03:13                 # `int`s can be inferred
Apr 08 19:03:13                 self.my_int = 10
Apr 08 19:03:13 
Apr 08 19:03:13             def forward(self, input):
Apr 08 19:03:13                 # type: (str) -> int
Apr 08 19:03:13                 self.words.append(input)
Apr 08 19:03:13                 return self.some_dict[input] + self.my_int
Apr 08 19:03:13 
Apr 08 19:03:13         f = torch.jit.script(Foo({'hi': 2}))
Apr 08 19:03:13 
Apr 08 19:03:13     |
Apr 08 19:03:13 Exception raised:
Apr 08 19:03:13     Traceback (most recent call last):
Apr 08 19:03:13       File "/opt/conda/lib/python3.6/doctest.py", line 1330, in __run
Apr 08 19:03:13         compileflags, 1), test.globs)
Apr 08 19:03:13       File "/opt/conda/lib/python3.6/site-packages/sphinx/ext/doctest.py", line 476, in compile
Apr 08 19:03:13         return compile(code, name, self.type, flags, dont_inherit)
Apr 08 19:03:13       File "<doctest default[0]>", line 29
Apr 08 19:03:13         .. testcode::
Apr 08 19:03:13         ^
Apr 08 19:03:13     SyntaxError: invalid syntax

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