Rewrite the callback and callable page

[kamil-tekiela]

No description provided.

[Copilot]

Pull Request Overview

This PR rewrites the PHP documentation page for callbacks and callables to provide a more comprehensive and up-to-date explanation. The rewrite restructures the content with improved organization, adds detailed examples, and includes information about modern PHP features like first-class callable syntax.

• Complete restructuring of content with clearer explanations and better organization
• Addition of comprehensive examples demonstrating different ways to create and use callables
• Updated information about PHP 8.1+ features and deprecation warnings for PHP 8.2+

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[kamil-tekiela]

This is what the page looks like now:

[TimWolla]

Thank you. Definitely an improvement. Some remarks.

[TimWolla]

I'll let someone else take another look, but LGTM from my side.

[afilina]

I reviewed the comments and LGTM. I don't see anything as blocking.