auto-round

a2b26c2a - docs: add Google-style docstrings to schemes, sign_sgd, envs, alg_ext

docs: add Google-style docstrings to schemes, sign_sgd, envs, alg_ext Add module-level docstrings and Google-style method/function docstrings to four core Python files without altering any code logic: - auto_round/schemes.py: module docstring; QuantizationScheme class and all its methods (from_dict, get_attributes, __getitem__, __setitem__, items, keys, values, get, __eq__); improved is_preset_scheme, _handle_special_schemes, and get_gguf_scheme. - auto_round/sign_sgd.py: module docstring; _RequiredParameter.__repr__, _use_grad_for_differentiable decorator, SignSGD.__setstate__; improved sgd and _single_tensor_sgd. - auto_round/envs.py: module docstring; __getattr__, __dir__; improved is_set. - auto_round/alg_ext.py: module docstring; wrapper_autoround, qdq_mxfp, mx_init, nv_fp4, nv_init, make_qp_quants, make_qp_new_quants, _register_act_max_hook_ext; improved wrapper_block_v2 and dq_wrapper_block. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>