[gtk/bilelmoussaoui/g-i: 3/5] g-i: mark get_selected_printer as nullable

[Bilal Elmoussaoui <bilelmoussaoui src gnome org>]

commit 6b638686414fc4a7108f33a7aee38717a13dddb7
Author: Bilal Elmoussaoui <belmouss redhat com>
Date:   Fri Feb 11 12:05:42 2022 +0100

    g-i: mark get_selected_printer as nullable
    
    There is no selected printer if the user closes the dialog
    Fixes https://github.com/gtk-rs/gtk4-rs/issues/882

 gtk/gtkprintunixdialog.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/gtk/gtkprintunixdialog.c b/gtk/gtkprintunixdialog.c
index 6c1ff5c260..d6c98d41ec 100644
--- a/gtk/gtkprintunixdialog.c
+++ b/gtk/gtkprintunixdialog.c
@@ -3078,7 +3078,7 @@ gtk_print_unix_dialog_new (const char *title,
  *
  * Gets the currently selected printer.
  *
- * Returns: (transfer none): the currently selected printer
+ * Returns: (transfer none) (nullable): the currently selected printer
  */
 GtkPrinter *
 gtk_print_unix_dialog_get_selected_printer (GtkPrintUnixDialog *dialog)