Make autoload exception more specific (#777)

This is a nice-to-have ([as I'm currently overriding it](psalm/psalm-plugin-laravel@a700c89)), but might help other packages.

src/Console/MetaCommand.php

@@ -135,7 +135,7 @@ protected function getAbstracts()
     protected function registerClassAutoloadExceptions()
     {
         spl_autoload_register(function ($class) {
-            throw new \Exception("Class '$class' not found.");
+            throw new \ReflectionException("Class '$class' not found.");
         });
     }