cmd/pkgserver: fix multi-line JS test output display

cmd/pkgserver/ui/static/run_tests.ts

@@ -1,4 +1,7 @@
 #!/usr/bin/env node
+// Many editors have terminal emulators built in, so running tests with NodeJS
+// provides faster iteration, especially for those acclimated to test-driven
+// development.
 import "./test_tests.js";
 import { run, StreamReporter } from "./test.js";
 run(new StreamReporter({ writeln: console.log }));