doc: add unreachable code on events example

PR-URL: #32364
Reviewed-By: Anna Henningsen <[email protected]>

Author: himself65

doc/api/events.md

@@ -887,6 +887,7 @@ const { on, EventEmitter } = require('events');
     // if concurrent execution is required.
     console.log(event); // prints ['bar'] [42]
   }
+  // Unreachable here
 })();
 ```