[gtk+] ToolItem: Fix nullable annotation put on wrong arg

[Daniel Boles <dboles src gnome org>]

commit c0fdf522dd890b028dba796d49b30fec772983ab
Author: Daniel Boles <dboles src gnome org>
Date:   Wed Sep 20 23:53:54 2017 +0100

    ToolItem: Fix nullable annotation put on wrong arg
    
    D’oh

 gtk/gtktoolitem.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/gtk/gtktoolitem.c b/gtk/gtktoolitem.c
index 09ee3ec..c809247 100644
--- a/gtk/gtktoolitem.c
+++ b/gtk/gtktoolitem.c
@@ -899,9 +899,9 @@ gtk_tool_item_rebuild_menu (GtkToolItem *tool_item)
 
 /**
  * gtk_tool_item_set_proxy_menu_item:
- * @tool_item: (nullable): a #GtkToolItem
+ * @tool_item: a #GtkToolItem
  * @menu_item_id: a string used to identify @menu_item
- * @menu_item: a #GtkMenuItem to be used in the overflow menu
+ * @menu_item: (nullable): a #GtkMenuItem to use in the overflow menu, or %NULL
  * 
  * Sets the #GtkMenuItem used in the toolbar overflow menu. The
  * @menu_item_id is used to identify the caller of this function and