Replace nonexistent "getAffectedRows"

Example incorrectly references a DB function "getAffectedRows" which should be "affectedRows"

Author: MGatner

user_guide_src/source/database/examples.rst

@@ -87,7 +87,7 @@ Standard Insert
 
 	$sql = "INSERT INTO mytable (title, name) VALUES (".$db->escape($title).", ".$db->escape($name).")";
 	$db->query($sql);
-	echo $db->getAffectedRows();
+	echo $db->affectedRows();
 
 Query Builder Query
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