docs: add missing api sample docs

[yoonhyejin]

Checklist

• The PR conforms to DataHub's Contributing Guideline (particularly Commit Message Format)
• Links to related issues (if applicable)
• Tests for the changes have been added/updated (if applicable)
• Docs related to the changes have been added/updated (if applicable). If a new feature has been added a Usage Guide has been added for the same.
• For any breaking change/potential downtime/deprecation/big changes an entry has been made in Updating DataHub

[yoonhyejin]

@hsheth2 could you force-merge on this? not really sure why vercel fails without errors, yarn build works fine locally

[hsheth2]

@yoonhyejin given that the vercel build has failed consistently, I don't feel great about force merging it.

[hsheth2]

@yoonhyejin feels like there's a formatting issue here - can you try reproducing locally?