Pass position to HitData for window pointer hits

[z-jxy]

Objective

• Mouse position from On<Pointer<Move>> is None when accessing from an observer added to a window.
• Fixes Window Picking backend doesn't set HitData position #21778

Solution

• Pass position to HitData in bevy_picking::window::update_window_hits
• Update doc comment

Testing

The following now works:

use bevy::prelude::*;

fn main() {
    App::new()
        .add_plugins(DefaultPlugins)
        .add_systems(Startup, setup)
        .run();
}

fn setup(mut commands: Commands) {
    commands.spawn(Camera2d);
    commands
        .spawn(Window::default())
        .observe(|trigger: On<Pointer<Move>>| {
            assert!(
                trigger.hit.position.is_some(),
                "Position should not be None"
            );
        });
}

[github-actions]

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[alice-i-cecile]

@laundmo, can I get your review here?

[alice-i-cecile]

Oh wow, that's shockingly easy. Thanks!

[laundmo]

I had guessed it would be easy, it seemed like an oversight to me. That's why i made it a bug report and not a feature request.

I'm glad it could be someones first contribution to bevy!