docs: update missing docstrings

[dandhlee]

Thank you for opening a Pull Request! Before submitting your PR, there are a few things you can do to make sure it goes smoothly:

• Make sure to open an issue as a bug/issue before writing your code! That way we can discuss the change, evaluate designs, and agree on the general idea
• Ensure the tests and linter pass
• Code coverage does not decrease (if any source code was changed)
• Appropriate docs were updated (if necessary)

Adds docstrings that were missing in the public documentation. This caused some of the content to not be rendered and be missing.

Fixes b/260130444 🦕

[acocuzzo]

Thanks Dan!