feat: add Markdown formatting support for step content in test plans

[danhellem]

This pull request enhances the formatting of test case steps in Azure DevOps by supporting Markdown-to-HTML conversion and ensuring proper XML-escaping for safe storage. It introduces a new helper function to handle the formatting and updates both the implementation and tests to verify correct behavior for various Markdown features and HTML escaping.

Formatting and Conversion Enhancements:

• Added formatStepContent function in src/tools/test-plans.ts to convert Markdown markers (bold, italic, inline code, and links) to corresponding HTML tags, wrap the result in the ADO rich text envelope, and XML-escape the final string for storage.
• Updated convertStepsToXml to use formatStepContent for both step and expected result content, ensuring all step content is consistently formatted and escaped.

Testing Improvements:

• Added comprehensive tests in test/src/tools/test-plan.test.ts to verify that:
  • HTML tags in step content are properly XML-escaped.
  • Markdown bold and italic are converted to XML-escaped HTML.
  • Markdown inline code is converted to XML-escaped <CODE> tags.
  • Non-whitelisted HTML tags (e.g., <script>) are escaped and not rendered.
  • Markdown links are converted to XML-escaped anchor tags.

GitHub issue number

#1399 1398

Associated Risks

N/A

✅ PR Checklist

• I have read the contribution guidelines
• I have read the code of conduct guidelines
• Title of the pull request is clear and informative.
• 👌 Code hygiene
• 🔭 Telemetry added, updated, or N/A
• 📄 Documentation added, updated, or N/A
• 🛡️ Automated tests added, or N/A

🧪 How did you test it?

Updated tests and tested manually with success

[github-actions]

Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

Scanned Files

None

[aaudzei]

Approved with suggestion

[aaudzei]

unless there is a specific reason to use uppercase HTML tags I'd prefer more conventional <b>Text</b>