[docs] AutoModelWithLMHead(model_name, **kwargs)
`AutoModelWithLMHead.from_pretrained` cannot accept `output_attentions=True`

This [docstring](https://huggingface.co/transformers/model_doc/auto.html?highlight=transformers%20automodelwithlmhead#transformers.AutoModelWithLMHead) suggests that it can.

Thanks @jrvc for discovering!

```python
import transformers
modelname='Helsinki-NLP/opus-mt-en-de'
config_overrider={'output_attentions':True, 'output_hidden_states':True}
self.model = transformers.AutoModelWithLMHead.from_pretrained(modelname, **config_overrider)
=>
*** TypeError: __init__() got an unexpected keyword argument 'output_attentions'
```


I will dig deeper!
This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.
<|||||>unstale?<|||||>This was fixed with https://github.com/huggingface/transformers/pull/5665!