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/editor/src/display_map/wrap_map.rs

@@ -1207,7 +1207,7 @@ mod tests {
         log::info!("Wrap width: {:?}", wrap_width);
 
         let buffer = cx.update(|cx| {
-            if rng.gen() {
+            if rng.r#gen() {
                 MultiBuffer::build_random(&mut rng, cx)
             } else {
                 let len = rng.gen_range(0..10);