[gtk] tree list model: Add docs

[Matthias Clasen <matthiasc src gnome org>]

commit 231b76bdd1895d6b3dea1c529898fc9bcae0f23b
Author: Matthias Clasen <mclasen redhat com>
Date:   Sun Sep 16 23:06:19 2018 -0400

    tree list model: Add docs

 gtk/gtktreelistmodel.c | 10 ++++++++++
 1 file changed, 10 insertions(+)
---
diff --git a/gtk/gtktreelistmodel.c b/gtk/gtktreelistmodel.c
index 6904681c3e..cbbc073cf7 100644
--- a/gtk/gtktreelistmodel.c
+++ b/gtk/gtktreelistmodel.c
@@ -25,6 +25,16 @@
 #include "gtkintl.h"
 #include "gtkprivate.h"
 
+/**
+ * SECTION:gtktreelistmodel
+ * @Short_description: a List model that can create child models on demand
+ * @Title: GtkTreeListModel
+ * @See_also: #GListModel
+ *
+ * #GtkTreeListModel is a #GListModel implementation that can expand rows
+ * by creating new child list models on demand.
+ */
+
 enum {
   PROP_0,
   PROP_AUTOEXPAND,