Summary and description support for references

Author: hotrush

src/json/JsonReference.php

@@ -80,8 +80,8 @@ public static function createFromUri(string $uri, ?JsonPointer $jsonPointer = nu
      */
     public static function createFromReference(
         string $referenceURI,
-        string $summary = null,
-        string $description = null,
+        ?string $summary = null,
+        ?string $description = null
     ): JsonReference
     {
         $jsonReference = new JsonReference();