Add missing auditor auditQuerySingleton.

src/lib/auditors/queries.ts

+import type { Auditor } from "@auditors/core"
+import {
+  auditArray,
+  auditChain,
+  auditFunction,
+  auditTest,
+} from "@auditors/core"
+
+export function auditQuerySingleton(...auditors: Auditor[]) {
+  return auditChain(
+    auditArray(),
+    auditTest(
+      (values) => values.length <= 1,
+      "Parameter must be present only once in query",
+    ),
+    auditFunction((value) => value[0]),
+    ...auditors,
+  )
+}