Adap 209/update iceberg docs note

[VersusFacit]

resolves https://github.com/dbt-labs/adapters-team-private/issues/210

Problem

We added the docs flag to a Jinja macro where there was a placeholder but we'd like to add it to the main flag object as well.

Solution

Add the docs url to the flag itself.

Checklist

• [x] I have read the contributing guide and understand what's expected of me
• [x] I have run this code in development and it appears to resolve the stated issue
• [x] This PR includes tests, or tests are not required/relevant for this PR
• [x] This PR has no interface changes (e.g. macros, cli, logs, json artifacts, config files, adapter interface, etc) or this PR has already received feedback and approval from Product or DX

[github-actions[bot]]

Thank you for your pull request! We could not find a changelog entry for this change. For details on how to document a change, see the dbt-snowflake contributing guide.

[VersusFacit]

Proof of the warning with the link 👍