chore: Fix several style lints (#17488)

It's not comprehensive enough to start linting on `style` group, but
hey, it's a start.

Release Notes:

- N/A

crates/gpui/src/platform/test/platform.rs

@@ -145,7 +145,7 @@ impl TestPlatform {
     }
 
     pub(crate) fn did_prompt_for_new_path(&self) -> bool {
-        self.prompts.borrow().new_path.len() > 0
+        !self.prompts.borrow().new_path.is_empty()
     }
 }