window: Deprecate gtk_window_set_default_geometry()

We don't support geometries anymore.

gtk/gtkwindow.c

@@ -5233,6 +5233,9 @@ gtk_window_set_default_size (GtkWindow   *window,
  * gtk_window_set_geometry_hints.
  *
  * Since: 3.0
+ *
+ * Deprecated: 3.20: This function does noting. If you want to set a default
+ *     size, use gtk_window_set_default_size() instead.
  */
 void
 gtk_window_set_default_geometry (GtkWindow *window,

gtk/gtkwindow.h

@@ -443,7 +443,7 @@ GDK_AVAILABLE_IN_ALL
 gboolean gtk_window_parse_geometry   (GtkWindow   *window,
                                       const gchar *geometry);
 
-GDK_AVAILABLE_IN_ALL
+GDK_DEPRECATED_IN_3_20_FOR(gtk_window_set_default_size)
 void gtk_window_set_default_geometry (GtkWindow *window,
                                       gint       width,
                                       gint       height);