Task Guide (Natural Language Processing) example does not run properly with trainer.train()
Author: Shariar-Mozumder
Pull request: no

### System Info

- `transformers` version: 4.38.1
- Platform: Linux-6.1.58+-x86_64-with-glibc2.35
- Python version: 3.10.12
- Huggingface_hub version: 0.20.3
- Safetensors version: 0.4.2
- Accelerate version: 0.27.2
- Accelerate config: 	not found
- PyTorch version (GPU?): 2.1.0+cu121 (False)
- Tensorflow version (GPU?): 2.15.0 (False)
- Flax version (CPU?/GPU?/TPU?): 0.8.1 (cpu)
- Jax version: 0.4.23
- JaxLib version: 0.4.23

### Who can help?

@stevhliu 

> def preprocess_function(examples):
    return tokenizer(examples["text"], truncation=True)
    
In the above code after I put max_length=512 in tokenizer() function it worked. Should we change the docs?

### Information

- [X] The official example scripts
- [ ] My own modified scripts

### Tasks

- [X] An officially supported task in the `examples` folder (such as GLUE/SQuAD, ...)
- [ ] My own task or dataset (give details below)

### Reproduction

Run the example script in [https://huggingface.co/docs/transformers/en/tasks/sequence_classification](url) I get an error 
`The size of tensor a (1232) must match the size of tensor b (512) at non-singleton dimension 1`

### Expected behavior

The training should start after trainer.train()

Comments:
Hi, unfortunately I'm unable to reproduce your error! For clarification, we're talking about the sequence classification [notebook](https://colab.research.google.com/github/huggingface/notebooks/blob/main/transformers_doc/en/pytorch/sequence_classification.ipynb) and not the [`run_classification.py`](https://github.com/huggingface/transformers/blob/main/examples/pytorch/text-classification/run_classification.py) script?

I can confirm the same issue when following [this guide](https://huggingface.co/docs/transformers/tasks/sequence_classification).

I can also see the following issues/differences between that documentation and [this Colab notebook](https://colab.research.google.com/github/huggingface/notebooks/blob/main/transformers_doc/en/pytorch/sequence_classification.ipynb)
- The following libraries are not install 
	- evaluate 
	- scikit-learn 
	- torch 
	- accelerate
- The notebook uses a different model to the docs. I don't think this matters, but the docs use `"distilbert/distilbert-base-uncased"` whereas the notebook uses `"distilbert-base-uncased"` - I'm pretty sure these resolve to the same thing though

Yeah the `distilbert-base-uncased` model was recently moved to its own repo, and we can update the docs in a better way to install Accelerate, Evaluate, etc for sure.

However, I'm still unable to reproduce the issue 😅 I attached a minimal Colab notebook [here](https://colab.research.google.com/drive/1IDn4B6lpu_7qcyVzXssa8qoyZowAymjl?usp=sharing) without any real changes to the version in the docs and it is able to train successfully. Let me know if you're able to run it!

This issue has been automatically marked as stale because it has not had recent activity. If you think this still needs to be addressed please comment on this thread.

Please note that issues that do not follow the [contributing guidelines](https://github.com/huggingface/transformers/blob/main/CONTRIBUTING.md) are likely to be ignored.