fix: refer to example location not outline location in json formatter

[davidjgoss]

🤔 What's changed?

In the JSON formatter, use the line from the last referenced AST node to refer to examples from a scenario outline. In these cases there are two nodes referenced - one for the outline and one for the example.

⚡️ What's your motivation?

Fixes #2223.

🏷️ What kind of change is this?

• 🐛 Bug fix (non-breaking change which fixes a defect)

📋 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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[coveralls]

Coverage: 98.563%. Remained the same when pulling 306c8d7 on fix/json-formatter-examples-location into cd50dc2 on main.