Update examples.xml

Co-authored-by: Jordi Kroon <jordi@jordikroon.nl>

Author: lacatoire

reference/yar/examples.xml

@@ -78,7 +78,7 @@ var_dump($client->add(1, 2));
 var_dump($client->call("add", array(3, 2)));
 
 
-/* _add can not be called */
+/* _add cannot be called */
 var_dump($client->_add(1, 2));
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