[vala] gtk+-2.0: Mark MessageDialog constructor parameter, message_format, as nullable

[Rico Tzschichholz <ricotz src gnome org>]

commit 32b35098583703f25e600eebd3e628c433e39c4c
Author: Alistair Thomas <astavale yahoo co uk>
Date:   Wed Dec 13 16:10:20 2017 +0000

    gtk+-2.0: Mark MessageDialog constructor parameter, message_format, as nullable
    
    https://bugzilla.gnome.org/show_bug.cgi?id=791570

 vapi/gtk+-2.0.vapi                       |    2 +-
 vapi/packages/gtk+-2.0/gtk+-2.0.metadata |    1 +
 2 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/vapi/gtk+-2.0.vapi b/vapi/gtk+-2.0.vapi
index 908179d..990a106 100644
--- a/vapi/gtk+-2.0.vapi
+++ b/vapi/gtk+-2.0.vapi
@@ -2791,7 +2791,7 @@ namespace Gtk {
                public weak Gtk.Widget label;
                [CCode (has_construct_function = false, type = "GtkWidget*")]
                [PrintfFormat]
-               public MessageDialog (Gtk.Window? parent, Gtk.DialogFlags flags, Gtk.MessageType type, 
Gtk.ButtonsType buttons, string message_format, ...);
+               public MessageDialog (Gtk.Window? parent, Gtk.DialogFlags flags, Gtk.MessageType type, 
Gtk.ButtonsType buttons, string? message_format, ...);
                [PrintfFormat]
                public void format_secondary_markup (string message_format, ...);
                [PrintfFormat]
diff --git a/vapi/packages/gtk+-2.0/gtk+-2.0.metadata b/vapi/packages/gtk+-2.0/gtk+-2.0.metadata
index 53ead70..15d2e92 100644
--- a/vapi/packages/gtk+-2.0/gtk+-2.0.metadata
+++ b/vapi/packages/gtk+-2.0/gtk+-2.0.metadata
@@ -440,6 +440,7 @@ gtk_menu_tool_button_new.label nullable="1"
 GtkMessageDialog:buttons accessor_method="0"
 gtk_message_dialog_new ellipsis="1" printf_format="1"
 gtk_message_dialog_new.parent nullable="1"
+gtk_message_dialog_new.message_format nullable="1"
 gtk_message_dialog_new_with_markup ellipsis="1" printf_format="1"
 gtk_message_dialog_new_with_markup.parent nullable="1"
 gtk_message_dialog_format_secondary_markup ellipsis="1" printf_format="1"