Add documentation for torch.jit.Attribute and torch.jit.annotate (#54485)
Summary:
This is to prepare for new language reference spec that needs to describe `torch.jit.Attribute` and `torch.jit.annotate`
Pull Request resolved: https://github.com/pytorch/pytorch/pull/54485
Reviewed By: SplitInfinity, nikithamalgifb
Differential Revision: D27406843
Pulled By: gmagogsfm
fbshipit-source-id: 98983b9df0f974ed69965ba4fcc03c1a18d1f9f5
