Fix: replace Java 23 link with archived Wayback URL (original page blank)

[akrutitiwari24]

The current link for "Java 23: Key Concepts in Brief — Sergio Petrucci" (https://petrucci.dev/java23.html) loads a blank page. The Wayback Machine has a working capture:

https://web.archive.org/web/20241213171851/https://petrucci.dev/java23.html

This PR updates the entry in books/free-programming-books-langs.md to point to the archived page and adds a short note indicating the original page currently shows blank.

Verified the Wayback capture on 2025-10-30. Fixes #12315.

[eshellman]

download not available from IA either. let's remove it.