add mutability to docs (#17454)
Summary:
Not sure the best way to integrate this…I wrote something that focuses on mutability "vertically" through the stack. Should I split it up and distribute it into the various sections, or keep it all together?
Pull Request resolved: https://github.com/pytorch/pytorch/pull/17454
Differential Revision: D14222883
Pulled By: suo
fbshipit-source-id: 3c83f6d53bba9186c32ee443aa9c32901a0951c0
