Add PHPStan types

[HendrikN]

We all know that PHP is super awesome, of course! But it lacks some handy tooling, like generics, for example. While they are currently being re-evaluated, we're still years away from any kind of actual implementation.

Tools like Psalm or PHPStan (living in the phpdocs) would help our IDEs when dealing with the Collection and Itemresponses, providing better type inference for the entities they entail.

Psalm vs PHPStan
PHPStan is already supported by Illuminate\Support\Collection (and has more stars on GitHub), making it my preferred option.

For clarity, I'm not opting for making this package target some PHPStan level, just adding some @template-annotations for making our lives (and that of our IDE's) a little bit easier.

[JaZo]

Good idea, a PR is more than welcome! Eventually we'd like to use PHPStan in this project, but let's focus on DX first!

[bbrala]

👋

And yeah, PHPStan would be great to include. Actually kinda suprised we didn't get to that here already.

[HendrikN]

Alrighty, I'll see what I can do next couple of days. The issue may be closed but i'll keep that up to you guys