[Docs]: Document how to use Collections instead of arrays

[lotyp]

Describe the bug

Currently documentation says that Collections can be used

To Reproduce

https://active-record.wayof.dev/active-entities/retrieving-entities#collections

Media prove

Describe the solution you would like

1. Implement this PR: [PoC] Custom ActiveQuery collections based on an attribute #20
2. Document how to use Collections

Additional context

No response