docs: :memo: add class prop showcase

[devagja]

Overview

What is it?

• [ ] Feature / enhancement
• [ ] Bug
• [x] Docs / tests / types / typos

Description

https://github.com/BuilderIO/qwik/issues/4179#issuecomment-1546099581

Checklist:

• [ ] My code follows the developer guidelines of this project
• [ ] I have performed a self-review of my own code
• [ ] I have made corresponding changes to the documentation
• [ ] Added new tests to cover the fix / functionality

[bolt-new-by-stackblitz[bot]]

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[manucorporat]

Awesome!