Create structure for statistics cookies.

src/parser/token.rs

@@ -64,6 +64,7 @@ impl<'r, 's> Token<'r, 's> {
                 Object::InlineSourceBlock(_) => Box::new(std::iter::empty()),
                 Object::LineBreak(_) => Box::new(std::iter::empty()),
                 Object::Target(_) => Box::new(std::iter::empty()),
+                Object::StatisticsCookie(_) => Box::new(std::iter::empty()),
             },
             Token::Element(elem) => match elem {
                 Element::Paragraph(inner) => Box::new(inner.children.iter().map(Token::Object)),