Docs: fix outdated ScanCode output format references

[Vijya2024]

Fixes #4466

Summary

This PR updates the ScanCode documentation to fix outdated and inconsistent references
in the “ScanCode Output Format” tutorial.

Specifically:

• Updates links that pointed to /en/latest/ pages which are no longer available,
  replacing them with the stable documentation URLs.
• Aligns the “How to specify ScanCode Output Format” page with the
  “All Scan Output Options” reference.
• Removes or clarifies references to deprecated options such as --html-app,
  which no longer appear in the current scancode -h output.

This improves accuracy, avoids broken links, and reduces confusion for new users.

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Tasks

• Reviewed contribution guidelines
• PR is descriptively titled 📑 and links the original issue above 🔗
• Tests pass
• Commits are in a uniquely-named feature branch and has no merge conflicts 📁
• Updated documentation pages
• Updated CHANGELOG.rst (not applicable for documentation-only change)