tamer: xir::parse::ele::test: TODO regarding recovery strategy

The comment explains the issue.  I don't think the strategy is going to be a
desirable one, but I want to move on and observe in retrospect how it ought
to be handled.

The important part right now is that recovery is accounted for and possible,
which was a long-standing concern.

DEV-7145

tamer/src/xir/parse/ele/test.rs

@@ -321,6 +321,13 @@ fn multiple_child_elements_sequential() {
     );
 }
 
+// TODO: This error recovery seems to be undesirable,
+//     both consuming an element and skipping the requirement;
+//       it is beneficial only in showing that recovery is possible and
+//       accounted for.
+//  Let's revisit once we're further along and have concrete examples to
+//    determine if there is a proper umbrella recovery strategy,
+//      or if it needs to be configurable depending on context.
 #[test]
 fn child_error_and_recovery() {
     #[derive(Debug, PartialEq, Eq)]