Improve display of parallel jobs in rustdoc-gui tester script

src/tools/rustdoc-gui/tester.js

@@ -248,15 +248,17 @@ async function main(argv) {
         opts["jobs"] = 1;
         console.log("`--no-headless` option is active, disabling concurrency for running tests.");
     }
-
-    console.log(`Running ${files.length} rustdoc-gui (${opts["jobs"]} concurrently) ...`);
+    let jobs = opts["jobs"];
 
     if (opts["jobs"] < 1) {
+        jobs = files.length;
         process.setMaxListeners(files.length + 1);
     } else if (headless) {
         process.setMaxListeners(opts["jobs"] + 1);
     }
 
+    console.log(`Running ${files.length} rustdoc-gui (${jobs} concurrently) ...`);
+
     // We catch this "event" to display a nicer message in case of unexpected exit (because of a
     // missing `--no-sandbox`).
     const exitHandling = () => {