Allow `-OO` mode for `docstring_decorator` (#29689)
Fixes
```
File "/nix/store/rv8xdwghdad9jv2w86b8g08kan9l6ksm-python3.11-transformers-4.38.2/lib/python3.11/site-packages/transformers/models/auto/configuration_auto.py", line 987, in <module>
class AutoConfig:
File "/nix/store/rv8xdwghdad9jv2w86b8g08kan9l6ksm-python3.11-transformers-4.38.2/lib/python3.11/site-packages/transformers/models/auto/configuration_auto.py", line 1011, in AutoConfig
@replace_list_option_in_docstrings()
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/nix/store/rv8xdwghdad9jv2w86b8g08kan9l6ksm-python3.11-transformers-4.38.2/lib/python3.11/site-packages/transformers/models/auto/configuration_auto.py", line 966, in docstring_decorator
lines = docstrings.split("\n")
^^^^^^^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'split'
```
