add docmentation for the `Unix style pattern` matching feature that can be leverage for `data_files` into `load_dataset`

Unless I'm mistaken, it seems that in the new documentation it is no longer mentioned that you can use Unix style pattern matching in the `data_files` argument of the `load_dataset` method.

This feature was mentioned [here](https://huggingface.co/docs/datasets/loading_datasets.html#from-a-community-dataset-on-the-hugging-face-hub) in the previous documentation.

I'd love to hear your opinion @lhoestq , @albertvillanova and @stevhliu