[gtk+] docs: Add deprecation notice for GtkButton.set_focus_on_click()

[Emmanuele Bassi <ebassi src gnome org>]

commit c9916fbc58923f0a43b233934ecdad0592a0ebda
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Thu Jun 9 21:35:36 2016 +0100

    docs: Add deprecation notice for GtkButton.set_focus_on_click()
    
    To match the deprecation annotation on the function declaration.

 gtk/gtkbutton.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkbutton.c b/gtk/gtkbutton.c
index e24c065..2d675a1 100644
--- a/gtk/gtkbutton.c
+++ b/gtk/gtkbutton.c
@@ -2314,6 +2314,8 @@ gtk_button_get_use_stock (GtkButton *button)
  * application.
  *
  * Since: 2.4
+ *
+ * Deprecated: 3.20: Use gtk_widget_set_focus_on_click() instead
  **/
 void
 gtk_button_set_focus_on_click (GtkButton *button,