make descriptions less surprising

[davidjgoss]

🤔 What's changed?

Use remark-breaks to mimic the behaviour of GitHub comments etc where single line breaks are honoured without requiring an escape or double space.

⚡️ What's your motivation?

Fixes #225

🏷️ What kind of change is this?

• ⚡ New feature (non-breaking change which adds new behaviour)

📋 Checklist:

• I agree to respect and uphold the Cucumber Community Code of Conduct
• I've changed the behaviour of the code
  • I have added/updated tests to cover my changes.
• My change requires a change to the documentation.
  • I have updated the documentation accordingly.
• Users should know about my change
  • I have added an entry to the "Unreleased" section of the CHANGELOG, linking to this pull request.

---

This text was originally generated from a template, then edited by hand. You can modify the template here.

[olleolleolle]

Super-nice change, well-packaged. The remarkPlugins collection is neat.