feat(base_types): storage key hint in Storage class

[winsvega]

🗒️ Description

Print hint string if assigned in Storage class
Usage:

Op.SSTORE(post.store_next(0, hint="expected_result"), Op.MLOAD(0))
...
        post={
            runner_contract: Account(
                storage=post,
            )
        },

🔗 Related Issues

Surpasses #807

✅ Checklist

• All: Set appropriate labels for the changes.
• All: Considered squashing commits to improve commit history.
• All: Added an entry to CHANGELOG.md.
• All: Considered updating the online docs in the ./docs/ directory.
• Tests: All converted JSON/YML tests from ethereum/tests have been added to converted-ethereum-tests.txt.
• Tests: A PR with removal of converted JSON/YML tests from ethereum/tests have been opened.
• Tests: Included the type and version of evm t8n tool used to locally execute test cases: e.g., ref with commit hash or geth 1.13.1-stable-3f40e65.
• Tests: Ran mkdocs serve locally and verified the auto-generated docs for new tests in the Test Case Reference are correctly formatted.

[winsvega]

the only thing here about Storage class.

post.store_next(0, hint="expected_result")

when used like this it is unclear that 0 is the expected value. I was very confused

[marioevz]

Awesome, thanks!