chore: fix phpstan errors

src/BusProNet/XmlParser/AgeConstraintParserRegistry.php

@@ -53,6 +53,7 @@ class AgeConstraintParserRegistry
         return $this->mergeConstraintResults($results, $constraintData);
     }
 
+    /** @param list<AgeConstraintResult> $results */
     private function mergeConstraintResults(array $results, string $rawData): AgeConstraintResult
     {
         if (empty($results)) {