[gtk/gtk-3-24] ModelButton: Add Since annotation on new prop

[Daniel Boles <dboles src gnome org>]

commit 483d25f418a4d298a41c3f0a6dd12a58ba5d2983
Author: Daniel Boles <dboles src gmail com>
Date:   Mon Jul 2 20:31:45 2018 +0100

    ModelButton: Add Since annotation on new prop

 gtk/gtkmodelbutton.c | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/gtk/gtkmodelbutton.c b/gtk/gtkmodelbutton.c
index 1ed8cce15c..05153672de 100644
--- a/gtk/gtkmodelbutton.c
+++ b/gtk/gtkmodelbutton.c
@@ -1166,6 +1166,8 @@ gtk_model_button_class_init (GtkModelButtonClass *class)
    * If %TRUE, XML tags in the text of the button are interpreted as by
    * pango_parse_markup() to format the enclosed spans of text. If %FALSE, the
    * text will be displayed verbatim.
+   *
+   * Since: 3.24
    */
   properties[PROP_USE_MARKUP] =
     g_param_spec_boolean ("use-markup",