Improve code in 02_git_configuration_HiPerGator.ipynb

[magitz]

As noted in https://github.com/orgs/PracticumAI/discussions/4, the code in 02_git_configuration_HiPerGator.ipynb needs improvement.

• Clarify prompt/improve the handling of answers on key re-use
• Clarify name and email requests, suggested values, and error handling.

[magitz]

Fixed