Add back std::ascii::AsciiExt - it is required on stable
Add back std::ascii::AsciiExt - it is required on stable

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