[gnome-2048/arnaudb/wip/gtk4: 7/34] Use hide-on-close property.

[Arnaud B. <arnaudb src gnome org>]

commit 6ca3e1c4d78b7fa5d43a76eec0f61f3289049264
Author: Arnaud Bonatti <arnaud bonatti gmail com>
Date:   Tue Apr 28 07:35:08 2020 +0200

    Use hide-on-close property.

 data/congrats.ui     | 1 +
 src/game-window.vala | 3 ---
 2 files changed, 1 insertion(+), 3 deletions(-)
---
diff --git a/data/congrats.ui b/data/congrats.ui
index 64ac731..9434c3e 100644
--- a/data/congrats.ui
+++ b/data/congrats.ui
@@ -23,6 +23,7 @@
     <property name="text" translatable="yes">Congratulations!</property>
     <property name="resizable">False</property>
     <property name="buttons">none</property>
+    <property name="hide-on-close">True</property>
     <child internal-child="message_area">
       <object class="GtkBox">
         <child>
diff --git a/src/game-window.vala b/src/game-window.vala
index 0ebf48b..72c47d9 100644
--- a/src/game-window.vala
+++ b/src/game-window.vala
@@ -408,9 +408,6 @@ private class GameWindow : ApplicationWindow
                     new_game_cb ();
                 _congrats_dialog.hide ();
             });
-        _congrats_dialog.delete_event.connect ((response_id) => {
-                return _congrats_dialog.hide_on_delete ();
-            });
     }
 
     private inline void target_value_reached_cb (uint target_value)