Java 22 features checklist

[AloisSeckar]

One of the current goals is to implement demos for all new JEPs included in JDK 23

This issue works as a tracker for the respective tasks

• JEP 423 - Region Pinning for G1
• JEP 447 - Statements before super(...) (Preview)
• JEP 454 - Foreign Function & Memory API
• JEP 456 - Unnamed Variables & Patterns
• JEP 457 - Class-File API (Preview)
• JEP 458 - Launch Multi-File Source-Code Programs
• JEP 459 - String Templates (Second Preview)
• JEP 460 - Vector API (Seventh Incubator)
• JEP 461 - Stream Gatherers (Preview)
• JEP 462 - Structured Concurrency (Second Preview)
• JEP 463 - Implicitly Declared Classes and Instance Main Methods (Second Preview)
• JEP 464 - Scoped Values (Second Preview)