minor symfony#40287 [Config] Switched to non-null defaults in exception constructors (derrabus)

This PR was merged into the 5.2 branch.

Discussion
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[Config] Switched to non-null defaults in exception constructors

| Q             | A
| ------------- | ---
| Branch?       | 5.2
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| Tickets       | N/A
| License       | MIT
| Doc PR        | N/A

Follow-up to symfony#40271 on the 5.2 branch.

Commits
-------

2e865ac Switched to non-null defaults in exception constructors

Author: chalasr

src/Symfony/Component/Config/Exception/LoaderLoadException.php

@@ -19,13 +19,13 @@
 class LoaderLoadException extends \Exception
 {
     /**
-     * @param string     $resource       The resource that could not be imported
-     * @param string     $sourceResource The original resource importing the new resource
-     * @param int        $code           The error code
-     * @param \Throwable $previous       A previous exception
-     * @param string     $type           The type of resource
+     * @param string          $resource       The resource that could not be imported
+     * @param string|null     $sourceResource The original resource importing the new resource
+     * @param int|null        $code           The error code
+     * @param \Throwable|null $previous       A previous exception
+     * @param string|null     $type           The type of resource
      */
-    public function __construct(string $resource, string $sourceResource = null, int $code = null, \Throwable $previous = null, string $type = null)
+    public function __construct(string $resource, string $sourceResource = null, ?int $code = 0, \Throwable $previous = null, string $type = null)
     {
         $message = '';
         if ($previous) {