Docs finetuning callback example (#21216)
* add to documentation
* improve docstring
* fix docs
* skip doctest if torchvision missing
* missing space
* changelog
* fix mistake
* Empty-Commit
* empty commit to rerun ci
* try fixing doctest
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Co-authored-by: Jirka Borovec <6035284+Borda@users.noreply.github.com>
Co-authored-by: jirka <jirka.borovec@seznam.cz>
Co-authored-by: Deependu Jha <deependujha21@gmail.com>
