pytorch

3df398a3 - Update the QR documentation to include a warning about when the QR.backward is well-defined. (#43547)

Update the QR documentation to include a warning about when the QR.backward is well-defined. (#43547) Summary: As per title. Pull Request resolved: https://github.com/pytorch/pytorch/pull/43547 Reviewed By: mruberry Differential Revision: D23318829 Pulled By: albanD fbshipit-source-id: 4764ebe1ad440e881b1c4c88b16fb569ef8eb0fa