[gtk+] combobox: Document the popup window CSS node

[Matthias Clasen <matthiasc src gnome org>]

commit 54a6e032ca86de5a282e27a0a0cc298a27d32a1a
Author: Matthias Clasen <mclasen redhat com>
Date:   Fri Jan 15 17:47:08 2016 -0500

    combobox: Document the popup window CSS node

 gtk/gtkcombobox.c     |    5 +++--
 gtk/gtkcomboboxtext.c |    3 ++-
 2 files changed, 5 insertions(+), 3 deletions(-)
---
diff --git a/gtk/gtkcombobox.c b/gtk/gtkcombobox.c
index df7f52e..e3ec42d 100644
--- a/gtk/gtkcombobox.c
+++ b/gtk/gtkcombobox.c
@@ -94,8 +94,9 @@
  *
  * |[<!-- language="plain" -->
  * combobox
- * ╰── button.combo
- *     ╰── arrow
+ * ├── button.combo
+ * │    ╰── arrow
+ * ╰── window.popup
  * ]|
  *
  * GtkComboBox has a single CSS node with name combobox. It adds the
diff --git a/gtk/gtkcomboboxtext.c b/gtk/gtkcomboboxtext.c
index a465d8b..43410f3 100644
--- a/gtk/gtkcomboboxtext.c
+++ b/gtk/gtkcomboboxtext.c
@@ -76,7 +76,8 @@
  * |[<!-- language="plain" -->
  * combobox
  * ├── entry.combo
- * ╰── button.combo
+ * ├── button.combo
+ * ╰── window.popup
  * ]|
  *
  * GtkComboBoxText has a single CSS node with name combobox. It adds