Carry what no section or mark spelling writes, and drop the mark refusal

todo.md

@@ -103,7 +103,7 @@ detail is settled at its own milestone.
           CommonMark's own precedence between a directive and a code span, and collapsed
           `escaping: 'attribute'` into `none`. The escaper's link-opener scan skips emitted syntax
           to match: a `](` inside a directive escapes no text `[`.
-    - [ ] **2e4 — The carry's fallback triggers.** `spec/flavour.md` carries a node its section
+    - [x] **2e4 — The carry's fallback triggers.** `spec/flavour.md` carries a node its section
           cannot spell — an attrs key no section lists, a value that is not the section's type, an
           arg slot holding no bare token, marks no nesting spells — where the emitter still refuses,
           which leaves the refusals a container's own spelling owns. The flanking trigger 2e2