[gnome-tetravex] Show new-game button at end of game.

[Arnaud B. <arnaudb src gnome org>]

commit 63004f5ae8d06048348f6e7c2d4920cc51d9ec63
Author: Arnaud Bonatti <arnaud bonatti gmail com>
Date:   Mon Sep 16 23:33:31 2019 +0200

    Show new-game button at end of game.
    
    Or to be exact, not at finish,
    but when the scores dialog has
    been closed, as it feels good.

 src/gnome-tetravex.vala | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/src/gnome-tetravex.vala b/src/gnome-tetravex.vala
index 53e20a2..86de813 100644
--- a/src/gnome-tetravex.vala
+++ b/src/gnome-tetravex.vala
@@ -332,6 +332,8 @@ private class Tetravex : Gtk.Application
             window.destroy ();
         else if (score_dialog_action == ResponseType.OK)
             new_game ();
+        else
+            new_game_solve_stack.set_visible_child_name ("new-game");
     }
 
     private bool scores_dialog_visible = false; // security for #5