refactor(check-type-check-coverage): the ANTI-content failure line no longer claims a cause it cannot know

Every `absent` needle failed with "which is the other ledger's remedy". That
was true while the only anti-content assertions were cross-ledger ones; the
TEST_DEBT case now pins a route this gate withdrew rather than another
ledger's advice, and the sentence read false on exactly the four failures the
withdrawal's ablation produces. The line now states what the case pins and
leaves the cause to each case's own `why`, which already carries it.

Claude-Session: https://claude.ai/code/session_017ef78bLdybu3AffehKkhfk
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude

scripts/check-type-check-coverage.mjs

@@ -6469,8 +6469,8 @@ function selfTest() {
     for (const needle of c.absent) {
       if (c.message.includes(needle))
         failures.push(
-          `#11491 graduation remedy — ${c.label}: message STILL contains ${needle}, which is the other `
-            + `ledger's remedy. ${c.why}`,
+          `#11491 graduation remedy — ${c.label}: message STILL contains ${needle}, which this case pins `
+            + `as ABSENT -- another ledger's remedy, or a route this one no longer offers. ${c.why}`,
         );
     }
   }