Drop gtkcontainer.h includes

These includes are unused.

gtk/gtkmenubutton.c

@@ -381,7 +381,7 @@ gtk_menu_button_class_init (GtkMenuButtonClass *klass)
       g_param_spec_object ("align-widget",
                            P_("Align with"),
                            P_("The parent widget which the menu should align with."),
-                           GTK_TYPE_CONTAINER,
+                           GTK_TYPE_WIDGET,
                            GTK_PARAM_READWRITE);
 
   /**

gtk/gtkpathbar.h

@@ -18,7 +18,7 @@
 #ifndef __GTK_PATH_BAR_H__
 #define __GTK_PATH_BAR_H__
 
-#include "gtkcontainer.h"
+#include "gtkwidget.h"
 #include "gtkfilesystem.h"
 
 G_BEGIN_DECLS

gtk/gtksizegroup.c

@@ -21,7 +21,7 @@
 
 #include "gtkbuildable.h"
 #include "gtkbuilderprivate.h"
-#include "gtkcontainer.h"
+#include "gtkwidget.h"
 #include "gtkintl.h"
 #include "gtktypebuiltins.h"
 #include "gtkprivate.h"

gtk/gtkwidgetprivate.h

@@ -28,7 +28,6 @@
 #include "gtkwidget.h"
 
 #include "gtkactionmuxerprivate.h"
-#include "gtkcontainer.h"
 #include "gtkcsstypesprivate.h"
 #include "gtkeventcontrollerprivate.h"
 #include "gtklistlistmodelprivate.h"