Add training video link to table of contents documentation

[marcgabe15]

This PR adds a training video link for creating a workbook table of contents

[learn-build-service-prod]

Learn Build status updates of commit 0cdee17:

✅ Validation status: passed

File	Status	Preview URL	Details
docs/resources/samples/table-of-contents.md	✅Succeeded	View

For more details, please refer to the build report.

[learn-build-service-prod]

PoliCheck Scan Report

The following report lists PoliCheck issues in PR files. Before you merge the PR, you must fix all severity-1 and severity-2 issues. The AI Review Details column lists suggestions for either removing or replacing the terms. If you find a false positive result, mention it in a PR comment and include this text: #policheck-false-positive. This feedback helps reduce false positives in future scans.

✅ No issues found

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[alison-mk]

Hey Marc, thank so much for recording this video! Like we discussed offline, I'm going to set my review response as "Request changes". Let me know when you're ready for a second review.