[gtk+] docs: don't use <warning>

[William Jon McCann <mccann src gnome org>]

commit 334d34178ad2280a2f39b781d24bc06d3819304b
Author: William Jon McCann <william jon mccann gmail com>
Date:   Wed Feb 5 02:17:03 2014 -0500

    docs: don't use <warning>

 gtk/gtktreemodelsort.c |    5 ++---
 1 files changed, 2 insertions(+), 3 deletions(-)
---
diff --git a/gtk/gtktreemodelsort.c b/gtk/gtktreemodelsort.c
index 97577fe..e1c5d61 100644
--- a/gtk/gtktreemodelsort.c
+++ b/gtk/gtktreemodelsort.c
@@ -2769,9 +2769,8 @@ gtk_tree_model_sort_iter_is_valid_helper (GtkTreeIter *iter,
  * @tree_model_sort: A #GtkTreeModelSort.
  * @iter: A #GtkTreeIter.
  *
- * <warning><para>
- * This function is slow. Only use it for debugging and/or testing purposes.
- * </para></warning>
+ * > This function is slow. Only use it for debugging and/or testing
+ * > purposes.
  *
  * Checks if the given iter is a valid iter for this #GtkTreeModelSort.
  *