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/db/src/kvp.rs

@@ -20,7 +20,7 @@ pub trait Dismissable {
         KEY_VALUE_STORE
             .read_kvp(Self::KEY)
             .log_err()
-            .map_or(false, |s| s.is_some())
+            .is_some_and(|s| s.is_some())
     }
 
     fn set_dismissed(is_dismissed: bool, cx: &mut App) {