Update comment to use to_cow_str() for class_id()

[Buckram123]

Noticed that as_str() doesn't exist for ClassId. This PR changes comment for class_id() to use closest alternative

[Bromeon]

Thanks for the contribution. I do wonder if we should add a direct PartialEq<&str> impl in this case, so you could write:

// Before:
HttpRequest::class_id().to_cow_str() == "HTTPRequest"

// After:
HttpRequest::class_id() == "HTTPRequest"

This would save a string copy in some cases. I was already thinking about this for GString and StringName for a longer time, but for those it's quite a bit harder...

[Buckram123]

@Bromeon Great suggestion! Let me know if you want it implemented in this PR

[Bromeon]

Let me know if you want it implemented in this PR

Generally yes, but I think we should think about this a bit and get some more input first 🙂

---

There is a small risk that a == encourages stringy comparisons, i.e.

if class_id == "MyClass"

instead of

if class_id == MyClass::class_id()

which is more error-prone.

Potential alternative would be a named method like is_class("...") or so, but then again that might be so niche that to_cow_str() is perfectly fine? 🤔

[GodotRust]

API docs are being generated and will be shortly available at: https://godot-rust.github.io/docs/gdext/pr-1412

[Bromeon]

Seeing how the similar PR #1415 got a bit more involved, maybe we should address the == later, if we have actual use cases. Until then, we can already merge this. Thank you! 🙂