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[docs] Clarify the fact that predict() on a file does not support saved Datasets (fixes #4034) (#4545)

* documentation changes

* add list of supported formats to error message

* add unit tests

* Apply suggestions from code review
Co-authored-by: Nikita Titov <nekit94-08@mail.ru>

* update per review comments

* make references consistent
Co-authored-by: Nikita Titov <nekit94-08@mail.ru>