Missing docs of macros and parameters for the readme

[dbeatty10]

Describe the feature

• As a user, I would like all macros within dbt_utils to appear in the documentation in the readme.
• As a contributor, I would like some mechanism to verify any new macros are added to the docs.

Currently, under-documented macros can be added/edited if a maintainer doesn't catch it.

Describe alternatives you've considered

1. Manually verify by adding an item to a checklist that contributors and maintainers go through as part of code review process.
2. Automatically verify during CI.
3. Automatically generate documentation somehow (possibly like how macro documentation works for dbt docs)

Who will this benefit?

• end users
• contributors
• maintainers

[dbeatty10]

For further background and motivation, see these issues:

• Add table of contents to README.md #346
• dbt_utils.safe_cast not listed as function in README.md #392
• not_accepted_values not listed at the top of the readme #399

[github-actions]

This issue has been marked as Stale because it has been open for 180 days with no activity. If you would like the issue to remain open, please comment on the issue or else it will be closed in 7 days.

[github-actions]

Although we are closing this issue as stale, it's not gone forever. Issues can be reopened if there is renewed community interest. Just add a comment to notify the maintainers.