Oops, my new json retriever forgot to append ?callback= at all.

I got so hung up testing services that ignore the callback= parameter that I
forgot to test ones that *don't* ignore it, thus missing a typo.
diff --git a/render.js b/render.js
index faaa028..b0e9fc5 100644
--- a/render.js
+++ b/render.js
@@ -1115,7 +1115,7 @@
         '<script async onerror="loaded" onload="loaded" src="' +
-        encodeURI(url) +
+        encodeURI(nurl) +