🐛 fix topics in koan AboutComparison

[peetrike]

PR Summary

fixes #450

Context

Changes

• fix topic 'It will compare values'
• fix topic 'It returns $true only if both inputs are $true'
• fix topic 'It may coerce values to boolean' (in context '-or')

Checklist

• Pull Request has a meaningful title.
• Summarised changes.
• Pull Request is ready to merge & is not WIP.
• Added tests / only testable interactively.
  • Make sure you add a new test if old tests do not effectively test the code changed.
• Added documentation / opened issue to track adding documentation at a later date.