recommend DeepSpeed's Argument Parsing documentation
# What does this PR do?

Clarify how to properly set the arguments passed by `deepspeed` when running in CLI.

For example the following errors might be raised when running something like `deepspeed --num_gpus=2 fine-tune.py google/flan-t5-xxl` due to args passed by `deepspeed`:

```
usage: fine-tune.py [-h] model_id                                                                                                      
fine-tune.py: error: unrecognized arguments: --local_rank=0 --deepspeed llms/flan-t5-fp16-z3.json                                      
usage: fine-tune.py [-h] model_id                                                                                                      
fine-tune.py: error: unrecognized arguments: --local_rank=1 --deepspeed llms/flan-t5-fp16-z3.json
```



## Before submitting
- [x] This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).


## Who can review?

Anyone in the community is free to review the PR once the tests have passed. Feel free to tag
members/contributors who may be interested in your PR.

@stas00 @sgugger 

cc @pacman100 <|||||>_The documentation is not available anymore as the PR was closed or merged._