Derive Debug for BloomCompositeMode (#11041)

# Objective

- API guidelines recommend that every type should implement `Debug`
where possible.

## Solution

- Do that.

crates/bevy_core_pipeline/src/bloom/settings.rs

@@ -175,7 +175,7 @@ pub struct BloomPrefilterSettings {
     pub threshold_softness: f32,
 }
 
-#[derive(Clone, Reflect, PartialEq, Eq, Hash, Copy)]
+#[derive(Debug, Clone, Reflect, PartialEq, Eq, Hash, Copy)]
 pub enum BloomCompositeMode {
     EnergyConserving,
     Additive,