Add Replay Feature and Enhanced Documentation
- Implemented replay functionality allowing players to replay the game.
- Enhanced README.md with detailed installation, usage instructions, and examples.
- Optimized code for better readability and maintainability.
- Removed redundant input validation for a smoother user experience.
- Ensured the game ends immediately after one player surpasses the target score.
- Improved project presentation by adding a guide for contributors and a more descriptive project overview.