chore: Bump Rust edition to 2024 (#27800)

Follow-up to https://github.com/zed-industries/zed/pull/27791

Release Notes:

- N/A

crates/feature_flags/src/feature_flags.rs

@@ -1,5 +1,5 @@
 use futures::channel::oneshot;
-use futures::{select_biased, FutureExt};
+use futures::{FutureExt, select_biased};
 use gpui::{App, Context, Global, Subscription, Task, Window};
 use std::cell::RefCell;
 use std::rc::Rc;