[gtk+] switch: Add a diagram to CSS node documentation

[Matthias Clasen <matthiasc src gnome org>]

commit 870461475a74c9dfb8835ed503702566203e8e2a
Author: Matthias Clasen <mclasen redhat com>
Date:   Tue Nov 3 13:28:52 2015 -0500

    switch: Add a diagram to CSS node documentation

 gtk/gtkswitch.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkswitch.c b/gtk/gtkswitch.c
index f747d74..7648209 100644
--- a/gtk/gtkswitch.c
+++ b/gtk/gtkswitch.c
@@ -38,6 +38,11 @@
  *
  * # CSS nodes
  *
+ * |[<!-- language="plain" -->
+ * switch
+ * ╰── slider
+ * ]|
+ *
  * GtkSwitch has two css nodes, the main node with the name switch and a subnode
  * named slider. Neither of them is using any style classes.
  */