Add missing Python function docstrings

[glenn-jocher]

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Enhanced code with improved documentation and minor code adjustments.

📊 Key Changes

• Added docstrings to the forward method in the YOLO model to describe its functionality.
• Updated docstrings for label rounding in dataloaders.py to clarify its purpose.
• Improved documentation for the TensorBoard SummaryWriter import in the logger utilities.

🎯 Purpose & Impact

• Enhanced Readability: The added and updated docstrings make the codebase easier to understand for developers, especially new contributors.
• Improved Maintainability: Clear documentation can aid in maintaining and extending the code.
• Better Debugging: Understanding each function's role helps in diagnosing issues more effectively.