Add a special case exit matcher for end of file.

src/parser/plain_list.rs

@@ -131,4 +131,16 @@ mod tests {
         assert_eq!(remaining, "");
         assert_eq!(result.source, "1.");
     }
+
+    #[test]
+    fn plain_list_item_simple() {
+        let input = "1. foo";
+        let initial_context: ContextTree<'_, '_> = ContextTree::new();
+        let document_context =
+            initial_context.with_additional_node(ContextElement::DocumentRoot(input));
+        let plain_list_item_matcher = parser_with_context!(plain_list_item)(&document_context);
+        let (remaining, result) = plain_list_item_matcher(input).unwrap();
+        assert_eq!(remaining, "");
+        assert_eq!(result.source, "1. foo");
+    }
 }