Fixes docs (#51439)
Summary:
pytorch_python_doc_build is failing with:
```
Jan 31 04:30:45 /var/lib/jenkins/workspace/docs/source/notes/broadcasting.rst:6: WARNING: 'any' reference target not found: numpy.doc.broadcasting
```
this removes the incorrect reference and adds an updated link.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/51439
Reviewed By: ngimel
Differential Revision: D26170232
Pulled By: mruberry
fbshipit-source-id: 829999db52e1e860d36d626d0d9f26e31283d14b
