Fix a bunch of other low-hanging style lints (#36498)

- **Fix a bunch of low hanging style lints like unnecessary-return**
- **Fix single worktree violation**
- **And the rest**

Release Notes:

- N/A

crates/feature_flags/src/feature_flags.rs

@@ -14,7 +14,7 @@ struct FeatureFlags {
 }
 
 pub static ZED_DISABLE_STAFF: LazyLock<bool> = LazyLock::new(|| {
-    std::env::var("ZED_DISABLE_STAFF").map_or(false, |value| !value.is_empty() && value != "0")
+    std::env::var("ZED_DISABLE_STAFF").is_ok_and(|value| !value.is_empty() && value != "0")
 });
 
 impl FeatureFlags {