Wrong example in opus_gnome dataset card
## Describe the bug
I found that [the example on opus_gone dataset ](https://github.com/huggingface/datasets/tree/main/datasets/opus_gnome#dataset-summary) doesn't work.

## Steps to reproduce the bug
```python
 load_dataset("gnome", lang1="it", lang2="pl")
```
`"gnome"` should be `"opus_gnome"`

## Expected results
```bash
100%
1/1 [00:00<00:00, 42.09it/s]
DatasetDict({
    train: Dataset({
        features: ['id', 'translation'],
        num_rows: 8368
    })
})
```

## Actual results
```bash
 Couldn't find 'gnome' on the Hugging Face Hub either: FileNotFoundError: Couldn't find file at https://raw.githubusercontent.com/huggingface/datasets/main/datasets/gnome/gnome.py
```

## Environment info
- `datasets` version: 2.4.0
- Platform: Linux-5.4.0-120-generic-x86_64-with-glibc2.27
- Python version: 3.9.13
- PyArrow version: 9.0.0
- Pandas version: 1.4.3
