[gdk-pixbuf] gdk-pixbuf-scale: Fix retval introspection for scale_simple()

[Bastien Nocera <hadess src gnome org>]

commit f7c87d1d226588e5ea192afd3ef51f456bfb7f38
Author: Iñaki García Etxebarria <garetxe gmail com>
Date:   Sun Nov 5 15:03:03 2017 +0100

    gdk-pixbuf-scale: Fix retval introspection for scale_simple()
    
    Add nullable return introspection annotation for
    gdk_pixbuf_scale_simple() as per existing API documentation.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=789934

 gdk-pixbuf/gdk-pixbuf-scale.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gdk-pixbuf/gdk-pixbuf-scale.c b/gdk-pixbuf/gdk-pixbuf-scale.c
index a178553..e9514ef 100644
--- a/gdk-pixbuf/gdk-pixbuf-scale.c
+++ b/gdk-pixbuf/gdk-pixbuf-scale.c
@@ -336,7 +336,7 @@ gdk_pixbuf_composite_color (const GdkPixbuf *src,
  * For more complicated scaling/alpha blending see gdk_pixbuf_scale()
  * and gdk_pixbuf_composite().
  * 
- * Return value: (transfer full): the new #GdkPixbuf, or %NULL if not enough memory could be
+ * Return value: (nullable) (transfer full): the new #GdkPixbuf, or %NULL if not enough memory could be
  * allocated for it.
  **/
 GdkPixbuf *