transformers

9120ae7d - Fixes NoneType exception when topk is larger than one coupled with a small context in the Question-Answering pipeline (#11628)

Fixes NoneType exception when topk is larger than one coupled with a small context in the Question-Answering pipeline (#11628) * added fix to decode function. added test to qa pipeline tests * completed topk docstring * fixed formatting with black * applied style_doc to fix line length