feat: conditional return types for Eloquent\Collection::find()

[sebdesign]

• Added or updated tests
• Documented user facing changes
• Updated CHANGELOG.md

This was originally submitted here: laravel/framework#44459

Changes

Thanks to PHPStan's conditional return types, we can now infer what does the find method of the Eloquent Collection returns.
When the $key argument is an array or an Arrayable object, it returns a new collection with the found items.
In all other cases, it returns a single item, or the $default value.

[szepeviktor]

we can now infer what does the find method of the Eloquent Collection returns

Oh yes.
Thank you for this PR.

[canvural]

Thank you.

But also can you add tests to this file? (of course not for the support collection case) So we'll make sure it also works fine with the custom eloquent collections. If the tests doesn't pass, you might need to add find to the array here.

[sebdesign]

Hey @canvural, I've tested the return type for custom Eloquent collections.

Instead of adding the method name on the list for the base collection class, we need to check the method name on the eloquent collection class, because that's where the method is declared.

[canvural]

Thank you! Can you also resolve the conflict? Then if the CI is green, we can merge!

[canvural]

Thank you!