Document that gizmo depth_bias has no effect in 2D (bevyengine#10074)

crates/bevy_gizmos/src/lib.rs

@@ -154,14 +154,16 @@ pub struct GizmoConfig {
     pub line_perspective: bool,
     /// How closer to the camera than real geometry the line should be.
     ///
+    /// In 2D this setting has no effect and is effectively always -1.
+    ///
     /// Value between -1 and 1 (inclusive).
     /// * 0 means that there is no change to the line position when rendering
     /// * 1 means it is furthest away from camera as possible
     /// * -1 means that it will always render in front of other things.
     ///
     /// This is typically useful if you are drawing wireframes on top of polygons
     /// and your wireframe is z-fighting (flickering on/off) with your main model.
-    /// You would set this value to a negative number close to 0.0.
+    /// You would set this value to a negative number close to 0.
     pub depth_bias: f32,
     /// Configuration for the [`AabbGizmo`].
     pub aabb: AabbGizmoConfig,