make doLoadClassMetadata() methods private

Author: xabbuh

Mapping/Loader/AttributeLoader.php

@@ -77,7 +77,7 @@ public function loadClassMetadata(ClassMetadataInterface $classMetadata): bool
         return $success;
     }
 
-    public function doLoadClassMetadata(\ReflectionClass $reflectionClass, ClassMetadataInterface $classMetadata): bool
+    private function doLoadClassMetadata(\ReflectionClass $reflectionClass, ClassMetadataInterface $classMetadata): bool
     {
         $className = $reflectionClass->name;
         $loaded = false;