[Task] callback_unwrap -> PromiseOrValue

[dj8yfo]

Background

Callback_unwrap can link to [PromiseOrValue] abstraction https://github.com/near/near-sdk-rs/blob/master/examples/cross-contract-calls/high-level/src/lib.rs#L26

User Story

See link in doc from #[callback_unwrap] to PromiseOrValue. Near-macro was chosen as an entry point for documentation, which should endeavour to encompass the rest of the lib.

Acceptance Criteria

Resources & Additional Notes

No response

Priority

🔴 P4 : Normal

[7-falseparfait]

Mind if I take this issue?