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/collab/src/tests/random_project_collaboration_tests.rs

@@ -304,7 +304,7 @@ impl RandomizedTest for ProjectCollaborationTest {
                                         let worktree = worktree.read(cx);
                                         worktree.is_visible()
                                             && worktree.entries(false, 0).any(|e| e.is_file())
-                                            && worktree.root_entry().map_or(false, |e| e.is_dir())
+                                            && worktree.root_entry().is_some_and(|e| e.is_dir())
                                     })
                                     .choose(rng)
                             });