[DocTests Speech] Add doc tests for all speech models (#15031)

* fix_torch_device_generate_test

* remove @

* doc tests

* up

* up

* fix doctests

* adapt files

* finish refactor

* up

* save intermediate

* add more logic

* new change

* improve

* next try

* next try

* next try

* next try

* fix final spaces

* fix final spaces

* improve

* renaming

* correct more bugs

* finish wavlm

* add comment

* run on test runner

* finish all speech models

* adapt

* finish

utils/documentation_tests.txt

@@ -1,2 +1,7 @@
-docs/source/quicktour.rst
-docs/source/task_summary.rst
+src/transformers/models/wav2vec2/modeling_wav2vec2.py
+src/transformers/models/hubert/modeling_hubert.py
+src/transformers/models/wavlm/modeling_wavlm.py
+src/transformers/models/unispeech/modeling_unispeech.py
+src/transformers/models/unispeech_sat/modeling_unispeech_sat.py
+src/transformers/models/sew/modeling_sew.py
+src/transformers/models/sew_d/modeling_sew_d.py