[gtk] gtk-demo: Update text for the transitions demo

[Matthias Clasen <matthiasc src gnome org>]

commit 924e5105123a6d39391d1c2cce67ddcf752dd2a1
Author: Matthias Clasen <mclasen redhat com>
Date:   Wed Sep 30 11:19:12 2020 -0400

    gtk-demo: Update text for the transitions demo
    
    The fire is gone, but we have wobbly widgets!

 demos/gtk-demo/gltransition.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
---
diff --git a/demos/gtk-demo/gltransition.c b/demos/gtk-demo/gltransition.c
index c80b3fcc2b..6b49a3cea5 100644
--- a/demos/gtk-demo/gltransition.c
+++ b/demos/gtk-demo/gltransition.c
@@ -1,5 +1,5 @@
 /* OpenGL/Transitions
- * #Keywords: OpenGL, shader
+ * #Keywords: OpenGL, shader, effect
  *
  * Create transitions between pages using a custom fragment shader.
  *
@@ -9,7 +9,8 @@
  * The transitions work with arbitrary content. We use images, shaders
  * GL areas and plain old widgets to demonstrate this.
  *
- * The demo also shows some sample fire effects on the buttons.
+ * The demo also shows some over-the-top effects like wobbly widgets,
+ * and a an animated background.
  */
 
 #include <math.h>