Issue #3443379 by Mykola Antoshchuk: Drupal 10 compatibility fixes

src/Theme/Theme.php

@@ -106,7 +106,8 @@ class Theme {
   protected function discoverFiles($theme, $type) {
     $length = -(strlen($type) + 1);
 
-    $path = drupal_get_path('theme', $theme);
+    $path = \Drupal::service('extension.path.resolver')->getPath('theme', $theme);
+
     // Only look for files that match the 'something.preprocess.inc' pattern.
     $mask = '/.' . $type . '.inc$/';