[docstring] Fix docstring for `ASTFeatureExtractor`
Author: imsoumya18
Pull request: yes

# What does this PR do?

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Fixes #26638

## Who can review?

@ydshieh 


Comments:
@ydshieh Why am I getting this error?
![Screenshot from 2023-10-09 19-09-48](https://github.com/huggingface/transformers/assets/50456734/738d6d2e-c3e1-489e-9ae8-e6dc38a78891)


Could just try `pip install tensorrt` - may not be completely necessary for your docstring change though.

Also, I would try `make fix-copies` in your next commit as it looks like this was what made CI fail

It's just a warning. No big deal.

And please follow #26638: you need to run a command to perform some fix.

@ydshieh now have a look please. Just getting the same warning as before. Otherwise all are ok

![Screenshot from 2023-10-09 21-48-29](https://github.com/huggingface/transformers/assets/50456734/2977b288-7e78-4004-b574-237ffaa10d05)


You haven't done any fix but just remove one entry in the list to ignore. You should follow the issue page of this event.

Please run `python3 utils/check_docstrings.py --fix_and_overwrite` (or python)

Hi @imsoumya18 Do you encounter some issues when running `python3 utils/check_docstrings.py --fix_and_overwrite`? 

> Hi @imsoumya18 Do you encounter some issues when running `python3 utils/check_docstrings.py --fix_and_overwrite`?

Yes, I am continuously getting this error
![image](https://github.com/huggingface/transformers/assets/50456734/481c93bd-767d-4929-a5b9-e7009979ca50)


I see, but I don't think it is an error, but just warning.

After you run that command, no file has being changed by the script? If so, I will take a look (but in this case, probably indeed an environment issue).

> I see, but I don't think it is an error, but just warning.
> 
> After you run that command, no file has being changed by the script? If so, I will take a look (but in this case, probably indeed an environment issue).

After it, no file was changed. But, I think (I maybe wrong) it's an error. Maybe a problem of the env. Also, I gave up hope and completely deleted the fork and repo whole. Let me fork and setup the env and check if the issue is solved. I will then open a new PR or reopen this one. Let me try again by setting up from start.

@imsoumya18 No worry, thank you for the effort. Environment is indeed frustrated, but maybe a new fresh python virtual environment is easy way. Let me know if you need any help. Look forward to your contribution 🔥