BULK Fix broken link

[v-thepet]

This PR contains fixes to broken links. Link target was permanently removed by Sapien. For work item request details see 558724

PR Summary

PR Checklist

• Descriptive Title: This PR's title is a synopsis of the changes it proposes.
• Summary: This PR's summary describes the scope and intent of the change.
• Contributor's Guide: I have read the contributor's guide.
• Style: This PR adheres to the style guide.

[Copilot]

Pull request overview

This PR fixes a broken outbound link in the PowerShell 101 “Introduction” page by removing an author bibliography entry that referenced a dead URL.

Changes:

• Removed the “Windows PowerShell TFM 4th Edition” bibliography bullet from the author section.
• Removed the corresponding dead link reference definition ([tfm4]) from the link reference block.

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[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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[learn-build-service-prod]

Learn Build status updates of commit 9891833:

✅ Validation status: passed

File	Status	Preview URL	Details
reference/docs-conceptual/learn/ps101/00-introduction.md	✅Succeeded	View (>=powershell-5.1)

For more details, please refer to the build report.

[v-thepet]

Link target was permanently removed by Sapien. #sign-off