[fix lint warnings: NFTs pallet] fix clippy::missing_errors_doc lint warnings (#14648)

* fix missing errors doc warnings

* cargo +nightly fmt

* Update frame/nfts/src/features/create_delete_item.rs

* Update frame/nfts/src/features/create_delete_item.rs

* Update frame/nfts/src/features/transfer.rs

* Update frame/nfts/src/features/create_delete_collection.rs

* add intra doc linking for errors

* fmt

* Apply suggestions from code review

Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

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Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>