Display (Player 1) or (Player 2) consistently

src/window/gdb.rs

@@ -42,13 +42,13 @@ impl GdbServerWindow {
 }
 
 impl AppWindow for GdbServerWindow {
-    fn sim_id(&self) -> SimId {
-        self.sim_id
+    fn sim_id(&self) -> Option<SimId> {
+        Some(self.sim_id)
     }
 
     fn initial_viewport(&self) -> ViewportBuilder {
         ViewportBuilder::default()
-            .with_title(format!("GDB Server ({})", self.sim_id))
+            .with_title("GDB Server")
             .with_inner_size((300.0, 200.0))
     }