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/diagnostics/src/diagnostic_renderer.rs

@@ -287,15 +287,13 @@ impl DiagnosticBlock {
                     }
                 }
             }
-        } else {
-            if let Some(diagnostic) = editor
-                .snapshot(window, cx)
-                .buffer_snapshot
-                .diagnostic_group(buffer_id, group_id)
-                .nth(ix)
-            {
-                Self::jump_to(editor, diagnostic.range, window, cx)
-            }
+        } else if let Some(diagnostic) = editor
+            .snapshot(window, cx)
+            .buffer_snapshot
+            .diagnostic_group(buffer_id, group_id)
+            .nth(ix)
+        {
+            Self::jump_to(editor, diagnostic.range, window, cx)
         };
     }
 

crates/diagnostics/src/diagnostics.rs

@@ -383,12 +383,10 @@ impl ProjectDiagnosticsEditor {
             } else {
                 self.update_all_diagnostics(false, window, cx);
             }
+        } else if self.update_excerpts_task.is_some() {
+            self.update_excerpts_task = None;
         } else {
-            if self.update_excerpts_task.is_some() {
-                self.update_excerpts_task = None;
-            } else {
-                self.update_all_diagnostics(false, window, cx);
-            }
+            self.update_all_diagnostics(false, window, cx);
         }
         cx.notify();
     }
@@ -542,7 +540,7 @@ impl ProjectDiagnosticsEditor {
                     return true;
                 }
                 this.diagnostics.insert(buffer_id, diagnostics.clone());
-                return false;
+                false
             })?;
             if unchanged {
                 return Ok(());