chore: Prepare for Rust edition bump to 2024 (without autofix) (#27791)

Successor to #27779 - in this PR I've applied changes manually, without
futzing with if let lifetimes at all.

Release Notes:

- N/A

crates/audio/src/assets.rs

@@ -35,7 +35,7 @@ impl SoundRegistry {
         cx.set_global(GlobalSoundRegistry(SoundRegistry::new(source)));
     }
 
-    pub fn get(&self, name: &str) -> Result<impl Source<Item = f32>> {
+    pub fn get(&self, name: &str) -> Result<impl Source<Item = f32> + use<>> {
         if let Some(wav) = self.cache.lock().get(name) {
             return Ok(wav.clone());
         }