API Code Comments
For each API project, the Gaming Services Doc team had a process somewhat like this to add and enhance comments in code (C#):
Create a docs branch from the repo (if that was the strategy preferred by the devs on this team).
Copy & Paste code from the repo or our local copy to a shared Google Drive.
Edit or add comments using XML guidelines.
Ask devs questions to clarify comments.
Using Slack, alert devs and other stakeholders about the comments in case they didn't notice the Google notification.
Resolve comments.
Discuss steps for merging new comments back to the repo with dev (each team had different strategies).
Coordinate with team that was running a swagger-type tool to automate the production of API docs if relevant to this project.
Double-check the Unity interface to see if the comments and new code was successfully updated to the customer-facing package docs.