Added documentation for branches

[janechu]

Pull Request

📖 Description

This change adds documentation for the naming and creation of branches.

✅ Checklist

General

• [ ] I have added tests for my changes.
• [ ] I have tested my changes.
• [x] I have updated the project documentation to reflect my changes.

[janechu]

@EisenbergEffect i'll request a review from @nicholasrice but that is what i was thinking.