Support QuestionAnswering Module for ModernBert based models. (#35566)

* push ModernBertForQuestionAnswering

* update ModernBertForQuestionAnswering

* update __init__ loading

* set imports for ModernBertForQuestionAnswering

* update ModernBertForQuestionAnswering

* remove debugging logs

* update init_weights method

* remove custom initialization for ModernBertForQuestionAnswering

* apply make fix-copies

* apply make style

* apply make fix-copies

* append ModernBertForQuestionAnswering to the pipeline supported models

* remove unused file

* remove invalid autoload value

* update en/model_doc/modernbert.md

* apply make fixup command

* make fixup

* Update dummies

* update usage tips for ModernBertForQuestionAnswering

* update usage tips for ModernBertForQuestionAnswering

* add init

* add lint

* add consistency

* update init test

* change text to trigger stuck text

* use self.loss_function instead of custom loss

By @Cyrilvallez

Co-authored-by: Cyril Vallez <cyril.vallez@gmail.com>

* Update modeling_modernbert.py

make comparable commit to even it out

* Match whitespace

* whitespace

---------

Co-authored-by: Matt <rocketknight1@gmail.com>
Co-authored-by: Orion Weller <wellerorion@gmail.com>
Co-authored-by: Orion Weller <31665361+orionw@users.noreply.github.com>
Co-authored-by: Cyril Vallez <cyril.vallez@gmail.com>

tests/test_modeling_common.py

@@ -3086,6 +3086,7 @@ class ModelTesterMixin:
                 "ModernBertForSequenceClassification",
                 "ModernBertForTokenClassification",
                 "TimmWrapperForImageClassification",
+                "ModernBertForQuestionAnswering",
             ]
             special_param_names = [
                 r"^bit\.",