add comment on why these are strings

src/routes/reverseproxy.js

@@ -25,6 +25,7 @@ async function getTrustedIps(req, res, next) {
 async function setTrustedIps(req, res, next) {
     assert.strictEqual(typeof req.body, 'object');
 
+    // this is a string to allow comments
     if (typeof req.body.trustedIps !== 'string') return next(new HttpError(400, 'trustedIps must be a string'));
 
     const [error] = await safe(reverseProxy.setTrustedIps(req.body.trustedIps, AuditSource.fromRequest(req)));