[gtk/constraints-grid: 2/4] Rename the constraints demo

[Matthias Clasen <matthiasc src gnome org>]

commit 68f6fe77326006a24ae45e8a864ea285843c98e1
Author: Matthias Clasen <mclasen redhat com>
Date:   Tue Jun 25 04:54:27 2019 +0000

    Rename the constraints demo
    
    We're going to add another one, so
    move them a level down in the tree.

 demos/gtk-demo/constraints.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/demos/gtk-demo/constraints.c b/demos/gtk-demo/constraints.c
index cc6cac145e..e0ff58bb9c 100644
--- a/demos/gtk-demo/constraints.c
+++ b/demos/gtk-demo/constraints.c
@@ -1,4 +1,4 @@
-/* Constraints
+/* Constraints/Simple
  *
  * GtkConstraintLayout provides a layout manager that uses relations
  * between widgets (also known as "constraints") to compute the position