bug #18752 [configuration][override_dir_structure] autoload to autoload_runtime (IssamRaouf)

This PR was merged into the 5.4 branch.

Discussion
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[configuration][override_dir_structure] autoload to autoload_runtime

From Symfony 5.3 we use autoload_runtime instead of autoload

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Commits
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e95def3 [configuration][override_dir_structure] autoload to autoload_runtime

Author: OskarStark

configuration/override_dir_structure.rst

@@ -254,7 +254,7 @@ your ``index.php`` front controller. If you renamed the directory, you're fine.
 But if you moved it in some way, you may need to modify these paths inside those
 files::
 
-    require_once __DIR__.'/../path/to/vendor/autoload.php';
+    require_once __DIR__.'/../path/to/vendor/autoload_runtime.php';
 
 You also need to change the ``extra.public-dir`` option in the ``composer.json``
 file: