Fix docs for distiset.save_to_disk kwargs

[fpreiss]

The keyword argument for the path in Distiset.save_to_disk should be documented as distiset_path instead of dataset_path.

[plaguss]

Thanks for the catch @fpreiss! 😃

[codspeed-hq]

CodSpeed Performance Report

Merging #745 will not alter performance

_{Comparing fpreiss:main (9065675) with main (3910aca)}

Summary

✅ 1 untouched benchmarks