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/workspace/src/modal_layer.rs

@@ -48,6 +48,12 @@ pub struct ModalLayer {
     dismiss_on_focus_lost: bool,
 }
 
+impl Default for ModalLayer {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl ModalLayer {
     pub fn new() -> Self {
         Self {