chore: add notebook links to img cls and obj det.
_The documentation is not available anymore as the PR was closed or merged._ @nateraw I guess the failing test is unrelated.   @sayakpaul Yea failures are unrelated.  Alright. Will wait for @osanseviero's take and then merge.  FYI @stevhliu  @osanseviero @stevhliu @nateraw thank you for your comments. Acted on them. Thanks! Can I merge? Or should we wait for approvals from the others? Since @stevhliu approved as well, I think you're good to go Alright!

Merging as a Member for the first time 🫀
Closes https://github.com/huggingface/datasets/issues/5182