Issue #3483437: Fixes fatal error on Drush 13.

Closes #3483437

src/Commands/MarkdownCommands.php

@@ -100,7 +100,16 @@ class MarkdownCommands extends DrushCommands implements ContainerInjectionInterf
   public function __construct(FileSystemInterface $fileSystem, LoggerInterface $logger) {
     parent::__construct();
     $this->fileSystem = $fileSystem;
-    $this->logger = $logger;
+
+    // Don't replace Drush's logger because it'll cause a fatal error on Drush
+    // 13 and newer.
+    //
+    // @see https://www.drupal.org/project/markdown/issues/3483437
+    //
+    // @see https://github.com/drush-ops/drush/pull/5022
+    if (!method_exists($this, 'logger')) {
+      $this->logger = $logger;
+    }
 
     if (!static::$shutdownRegistered) {
       drupal_register_shutdown_function(function () {