doc: add links from each near-macro attribute to host functions from [env] module related to it and used in implementation

[dj8yfo]

• #[payable] could link to [env::attached_deposit]

• #[private] could link to [env::predecessor_account_it] and [env::panic_str]

• #[handle_result] depends on [env::value_return] and [env::panic_str] - covered in scope of doc: #[near(contract_state)] in-depth pass #1307 , only needs a backlink added to anchor it's mentioned in

• #[serializer(...)]# (method arg) - covered in scope of doc: #[near(contract_state)] in-depth pass #1307 , only needs a backlink added to anchor it's mentioned in

• #[callback_vec] depends on [env::promise_results_count] (this depends on doc: document callback_... family of near-macro sub-attributes #1300 and intersects with scope of doc: add discovered intra-doc links and urls with usages within repo to rustdoc of near-sdk #1265 )

• ..n. under scrutiny, most of attributes can be linked to host-functions they depend on in implementation

---

This task should add implementation details for each attribute in the spirit of #1307 , by
checking cargo expand --lib --target wasm32-unknown-unknown output with and without
#[documented_attr], and digging into near-sdk-macros if that doesn't help

relates to #1299

[TobieTom]

May I take care of this? Im new in the space and looking to add on to my experience

[dj8yfo]

@TobieTom you can try doing #1305. Each individual attrubute should have a compact pr, which is easy to review and drive to completion. A single pr for the whole task would be a much bigger chunk, besides this issue has unresolved issue #1300 it depends on for full completion

[7-falseparfait]

Mind if I try this one?

[frol]

@TobieTom @7-falseparfait I think it would be great learning exercise even if you will end up having competing PRs - we will be able to merge and pick the best parts from each! Please, go ahead!