Docs: Replace void with null in union return types in link-template.php

[apermo]

Update 13 functions in link-template.php to use null instead of void in @return union types, and change bare return; statements to return null;.

In PHP's type system, void cannot be part of a union type. A bare return; actually returns null at runtime, so @return Type|null is the correct annotation.

Trac ticket: https://core.trac.wordpress.org/ticket/64699

Use of AI Tools

Used AI for research, documentation and for the replacements. Everything was reviewed by myself and @xateman before opening this PR.

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This Pull Request is for code review only. Please keep all other discussion in the Trac ticket. Do not merge this Pull Request. See GitHub Pull Requests for Code Review in the Core Handbook for more details.

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Props apermo, xate, westonruter, noruzzaman.

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[xateman]

Looks good 👍

[github-actions]

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[noruzzamans]

The modernization in link-template.php to replace void with null in union types looks solid and aligns with PHP standards. I appreciate the attention to detail in updating the function bodies as well—like the explicit return null; in get_edit_comment_link()—ensuring they match the new PHPDoc types. Everything is consistently implemented and follows the coding standards.

[westonruter]

@noruzzamans Are you using AI to write #11004 (review) and #11022 (review)? You should disclose this, if so, for example the model and how you prompted it. AI reviews can be helpful, but not if they don't add value; in the worst case, they can just add noise. (The em-dashes in your comment are a tell that AI was used.) Thanks!