Doc: Datasets doc

[codingl2k1]

What do these changes do?

Related issue number

Fixes https://github.com/xorbitsai/xorbits/issues/616

Check code requirements

• [ ] tests added / passed (if needed)
• [ ] Ensure all linting tests pass

[codecov[bot]]

Codecov Report

Merging #619 (5a295d8) into main (1c20af6) will decrease coverage by 17.41%. The diff coverage is 100.00%.

@@             Coverage Diff             @@
##             main     #619       +/-   ##
===========================================
- Coverage   93.62%   76.22%   -17.41%     
===========================================
  Files        1020     1020               
  Lines       79036    79039        +3     
  Branches    16395    16395               
===========================================
- Hits        73999    60244    -13755     
- Misses       3381    16501    +13120     
- Partials     1656     2294      +638     

Flag	Coverage Δ
unittests	76.11% <100.00%> (-17.42%)	:arrow_down:

Flags with carried forward coverage won't be shown. Click here to find out more.

Files Changed	Coverage Δ
...thon/xorbits/datasets/backends/huggingface/core.py	100.00% <ø> (ø)
python/xorbits/datasets/adapter.py	100.00% <100.00%> (ø)
python/xorbits/datasets/dataset.py	97.61% <100.00%> (+0.05%)	:arrow_up:

... and 274 files with indirect coverage changes