[gtk+/gtk-3-22] Expander: Replace (allow-none) with (nullable)

[Daniel Boles <dboles src gnome org>]

commit 7b08d11891ea1cbc3a581023f607fc9e91cf66fd
Author: Daniel Boles <dboles src gnome org>
Date:   Thu Sep 14 21:19:12 2017 +0100

    Expander: Replace (allow-none) with (nullable)
    
    The former is deprecated in favour of the latter.

 gtk/gtkexpander.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/gtk/gtkexpander.c b/gtk/gtkexpander.c
index 894a34a..bc6b90e 100644
--- a/gtk/gtkexpander.c
+++ b/gtk/gtkexpander.c
@@ -1231,7 +1231,7 @@ gtk_expander_new (const gchar *label)
 
 /**
  * gtk_expander_new_with_mnemonic:
- * @label: (allow-none): the text of the label with an underscore
+ * @label: (nullable): the text of the label with an underscore
  *     in front of the mnemonic character
  *
  * Creates a new expander using @label as the text of the label.
@@ -1376,7 +1376,7 @@ gtk_expander_get_spacing (GtkExpander *expander)
 /**
  * gtk_expander_set_label:
  * @expander: a #GtkExpander
- * @label: (allow-none): a string
+ * @label: (nullable): a string
  *
  * Sets the text of the label of the expander to @label.
  *
@@ -1555,7 +1555,7 @@ gtk_expander_get_use_markup (GtkExpander *expander)
 /**
  * gtk_expander_set_label_widget:
  * @expander: a #GtkExpander
- * @label_widget: (allow-none): the new label widget
+ * @label_widget: (nullable): the new label widget
  *
  * Set the label widget for the expander. This is the widget
  * that will appear embedded alongside the expander arrow.