trunk/2925147e1f1757dc764616c98e8a5a94ed8202b0: docs: make optimizer load_state_dict example generic (#185401)

Fixes #164932

Summary:

• Update the inherited Optimizer.load_state_dict example so generated optimizer docs do not point every optimizer page at torch.optim.SGD.


• Keep the example focused on the existing scheduler-before-optimizer load ordering guidance.

Test Plan:

• python3 -m py_compile torch/optim/optimizer.py


• git diff --check
  
  Pull Request resolved: #185401
  
  Approved by: https://github.com/janeyx99, https://github.com/cyyever