Rename "modified" event type to "object modified"

For clarification.

src/CsvxmlAvailableFields.php

@@ -1424,7 +1424,7 @@ public function __construct(string $lang) {
             55 => 'mentioned_time',
             56 => 'received_ownership',
             57 => 'transferred_ownership',
-            58 => 'modified',
+            58 => 'object_modified',
         ];
 
         foreach ($eventNamesByType as $eventType => $eventIdentifierCsvxml) {