[dia] autoptr: add a couple missing declarations

[Zander Brown <zbrown src gnome org>]

commit 4681a2593af00fa66840be4fadffdad73bac7a9d
Author: Zander Brown <zbrown gnome org>
Date:   Sat Jul 31 00:57:39 2021 +0100

    autoptr: add a couple missing declarations
    
    This is why we have CI people

 lib/dia-autoptr.h | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/lib/dia-autoptr.h b/lib/dia-autoptr.h
index f5c0200bb..5508030c5 100644
--- a/lib/dia-autoptr.h
+++ b/lib/dia-autoptr.h
@@ -41,5 +41,7 @@ G_DEFINE_AUTOPTR_CLEANUP_FUNC (GtkDialog, g_object_unref)
 G_DEFINE_AUTOPTR_CLEANUP_FUNC (GtkEventBox, g_object_unref)
 G_DEFINE_AUTOPTR_CLEANUP_FUNC (GtkTable, g_object_unref)
 G_DEFINE_AUTOPTR_CLEANUP_FUNC (GtkRadioButton, g_object_unref)
+G_DEFINE_AUTOPTR_CLEANUP_FUNC (GtkMisc, g_object_unref)
+G_DEFINE_AUTOPTR_CLEANUP_FUNC (GtkButton, g_object_unref)
 
 G_END_DECLS