CCK: Reconcile rules

[luke-hill]

rules is now is consistent for ruby/js.

I also massively removed the contradictory steps. Now it's at least consistent.

⚡️ What's your motivation?

Goes towards completion of issue in tracker

🏷️ What kind of change is this?

• 🏦 Refactoring/debt/DX (improvement to code design, tooling, documentation etc. without changing behaviour)
• 🐛 Bug fix (non-breaking change which fixes a defect)

♻️ Anything particular you want feedback on?

📋 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.

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[luke-hill]

@davidjgoss think my knowledge of the assert library might be a bit lacking here. This will probably need a fix. I couldn't find a beEmpty() function