add typehinting according to the contract

src/Fakes/FakeMetaCommand.php

@@ -6,13 +6,11 @@ use Barryvdh\LaravelIdeHelper\Console\MetaCommand;
 
 class FakeMetaCommand extends MetaCommand
 {
-    /**
-     * @return void
-     */
-    protected function registerClassAutoloadExceptions()
+    protected function registerClassAutoloadExceptions(): callable
     {
         // by default, the ide-helper throws exceptions when it cannot find a class. However it does not unregister that
         // autoloader when it is done, and we certainly do not want to throw exceptions when we are simply checking if
         // a certain class exists. We are instead changing this to be a noop.
+        return function () {};
     }
 }