[gtk+] menu: Document CSS nodes

[Matthias Clasen <matthiasc src gnome org>]

commit 25e01a3937c2e67cf40be2c50aae6d4edac5abc3
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon Nov 2 21:40:40 2015 -0500

    menu: Document CSS nodes

 gtk/gtkmenu.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkmenu.c b/gtk/gtkmenu.c
index 0409b54..ac516f0 100644
--- a/gtk/gtkmenu.c
+++ b/gtk/gtkmenu.c
@@ -82,6 +82,12 @@
  *   return FALSE;
  * }
  * ]|
+ *
+ * # CSS nodes
+ *
+ * The main CSS node of GtkMenu has name menu, and there are two subnodes
+ * with name arrow, for scrolling menu arrows. These subnodes get the
+ * .top and .bottom style classes.
  */
 
 #include "config.h"