[gtk+] treemodel: document gtk_tree_path_free() as allow-none

[Cosimo Cecchi <cosimoc src gnome org>]

commit 0c135cbf2c6e2af5d6be25b9a7f437198967c4a2
Author: Cosimo Cecchi <cosimoc gnome org>
Date:   Wed Oct 19 14:47:50 2011 -0400

    treemodel: document gtk_tree_path_free() as allow-none
    
    https://bugzilla.gnome.org/show_bug.cgi?id=662230

 gtk/gtktreemodel.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/gtk/gtktreemodel.c b/gtk/gtktreemodel.c
index 584e351..f0f7f41 100644
--- a/gtk/gtktreemodel.c
+++ b/gtk/gtktreemodel.c
@@ -874,9 +874,9 @@ gtk_tree_path_get_indices_with_depth (GtkTreePath *path,
 
 /**
  * gtk_tree_path_free:
- * @path: a #GtkTreePath
+ * @path: (allow-none): a #GtkTreePath
  *
- * Frees @path.
+ * Frees @path. If @path is %NULL, it simply returns.
  */
 void
 gtk_tree_path_free (GtkTreePath *path)