Update progressbar.rst

Author: peterjaap

components/console/helpers/progressbar.rst

@@ -106,11 +106,13 @@ which starts, advances and finishes the progress bar automatically::
     $progressBar = new ProgressBar($output);
 
     // $iterable can be for example an array ([1, 2, 3, ...])
-    foreach ($progressBar->iterate([1, 2, 3]) as $value) {
+    $iterable = [1, 2];
+    foreach ($progressBar->iterate($iterable) as $value) {
         // ... do some work
     }
+    
     // or a generator
-    // function iterable() { yield 1; yield 2; ... };
+    function iterable() { yield 1; yield 2; ... };
     foreach ($progressBar->iterate(iterable()) as $value) {
         // ... do some work
     }