docs: make technical prose concrete

scripts/doc-typecheck.ts

@@ -221,7 +221,7 @@ const { primary: all, derivatives } = partitionPairedMarkdownDerivatives(
 const checked = all.filter(b => b.kind === 'check')
 const ignored = all.filter(b => b.kind === 'ignore')
 // Only compile-eligible fences belong in the opt-out ratio; every other skipped
-// kind has an independent verifier named in BlockKind's contract above.
+// kind has an independent verifier named in the BlockKind rules above.
 const ratioDenominator = checked.length + ignored.length
 
 if (checked.length === 0) {