gtk-demo: Rename the transition shader files

Easier to find them when their name matches the title
that we show in the UI.

demos/gtk-demo/demo.gresource.xml

@@ -140,13 +140,13 @@
     <file>gtkshaderbin.c</file>
     <file>gskshaderpaintable.h</file>
     <file>gskshaderpaintable.c</file>
+    <file>wind.glsl</file>
+    <file>radial.glsl</file>
+    <file>crosswarp.glsl</file>
+    <file>kaleidoscope.glsl</file>
+    <file>cogs2.glsl</file>
     <file>ripple.glsl</file>
     <file>background.glsl</file>
-   <file>transition1.glsl</file>
-    <file>transition2.glsl</file>
-    <file>transition3.glsl</file>
-    <file>transition4.glsl</file>
-    <file>cogs2.glsl</file>
   </gresource>
   <gresource prefix="/iconscroll">
     <file>iconscroll.ui</file>

demos/gtk-demo/gltransition.c

@@ -320,16 +320,16 @@ create_gltransition_window (GtkWidget *do_widget)
   gtk_grid_set_column_homogeneous (GTK_GRID (grid), TRUE);
 
   gtk_grid_attach (GTK_GRID (grid),
-                   make_shader_stack ("Wind", "/gltransition/transition1.glsl", 0, scale),
+                   make_shader_stack ("Wind", "/gltransition/wind.glsl", 0, scale),
                    0, 0, 1, 1);
   gtk_grid_attach (GTK_GRID (grid),
-                   make_shader_stack ("Radial", "/gltransition/transition2.glsl", 1, scale),
+                   make_shader_stack ("Radial", "/gltransition/radial.glsl", 1, scale),
                    1, 0, 1, 1);
   gtk_grid_attach (GTK_GRID (grid),
-                   make_shader_stack ("Crosswarp", "/gltransition/transition3.glsl", 2, scale),
+                   make_shader_stack ("Crosswarp", "/gltransition/crosswarp.glsl", 2, scale),
                    0, 1, 1, 1);
   gtk_grid_attach (GTK_GRID (grid),
-                   make_shader_stack ("Kaleidoscope", "/gltransition/transition4.glsl", 3, scale),
+                   make_shader_stack ("Kaleidoscope", "/gltransition/kaleidoscope.glsl", 3, scale),
                    1, 1, 1, 1);
 
   return window;