feat: use a pensive face when the answer is wrong

[a2937]

Summary of changes

I turned the icons used into constant unicode expressions and added a state to determine if the user gave the correct answer. I also made the pre-commit script executable again.

Checklist

• [X] I have read and followed the contribution guidelines.
• [X] I have read through the Code of Conduct and agree to abide by the rules.
• [X] This PR is for one of the available issues and is not a PR for an issue already assigned to someone else.
• [X] My PR title has a short descriptive name so the maintainers can get an idea of what the PR is about.
• [X] I have provided a summary of my changes.

closes #950