Add placeholder tensor documentation for methods that exist in torch. (pytorch#463)

Author: colesbury

torch/__init__.py

@@ -245,5 +245,7 @@ def storage_type(cls):
 import torch.nn
 import torch.optim
 import torch.multiprocessing
-from . import docs  # attaches docstrings to torch functions
-del docs
+
+# attach docstrings to torch and tensor functions
+from . import _torch_docs, _tensor_docs
+del _torch_docs, _tensor_docs