docs(spec): leave data/object.form.ts to the open PR that now holds it (stage 3)

The #20432 PR opened after this stage's claim and edits
packages/spec/src/data/object.form.ts, so that file joins the stage's
exclusions. Its one comment site returns to the base bytes (blob 60713e0)
and waits for a later stage.

Claude-Session: https://claude.ai/code/session_014EJ1ED8X4MMrT18BhVx4tx
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude

packages/spec/src/data/object.form.ts

@@ -253,7 +253,7 @@ export const objectForm = defineForm({
             // the option shape is strict and has never declared `icon`, so a
             // Lucide name typed there was an `unrecognized_keys` refusal at
             // publish — the author found out at the 422, the same
-            // offer-vs-door class #11410 and commit c459da6bc retired elsewhere.
+            // offer-vs-door class #11410 and #12868 retired elsewhere.
             //
             // Remove rather than declare, on a premise measured for THIS
             // surface rather than inherited from #5016's action-param reading: