UndoManager: reorganize the order of the functions
UndoManager: reorganize the order of the functions

So prototypes are not needed.

uajain/gtksourceview,GNOME/gtksourceview,GNOME/gtksourceview,cburschka/gtksourceview,GNOME/gtksourceview,GNOME/gtksourceview,cburschka/gtksourceview,uajain/gtksourceview,uajain/gtksourceview,uajain/gtksourceview,cburschka/gtksourceview,GNOME/gtksourceview,GNOME/gtksourceview,cburschka/gtksourceview,cburschka/gtksourceview,cburschka/gtksourceview,uajain/gtksourceview,uajain/gtksourceview,GNOME/gtksourceview,uajain/gtksourceview,cburschka/gtksourceview,cburschka/gtksourceview,uajain/gtksourceview,uajain/gtksourceview,cburschka/gtksourceview,GNOME/gtksourceview,GNOME/gtksourceview,GNOME/gtksourceview,GNOME/gtksourceview,GNOME/gtksourceview,uajain/gtksourceview,GNOME/gtksourceview,cburschka/gtksourceview,GNOME/gtksourceview,GNOME/gtksourceview