Fix `OPTForQuestionAnswering` doctest (#19479)
Fix `OPTForQuestionAnswering` doctest (#19479)

* Fix doc example for OPTForQuestionAnswering

Co-authored-by: ydshieh <b8b5afdcc4de58b54ce28738b50f86ec989da691@users.noreply.github.com>
huggingface/transformers,huggingface/transformers,huggingface/transformers,huggingface/transformers