Codegen: use new glib macro for BoolError
Codegen: use new glib macro for BoolError

See https://github.com/gtk-rs/glib/pull/419

EPashkin/gir,gtk-rs/gir,EPashkin/gir,GuillaumeGomez/gir,GuillaumeGomez/gir,GuillaumeGomez/gir,gtk-rs/gir,gtk-rs/gir