Rule source on GitHub

DowngradeTrailingCommasInUnsetRector

Remove trailing commas in unset

 unset(
 	$x,
-	$y,
+	$y
 );

Configure your rector.php:

<?php

use Rector\Config\RectorConfig;
use Rector\DowngradePhp73\Rector\Unset_\DowngradeTrailingCommasInUnsetRector;

return RectorConfig::configure()
    ->withRules([
        DowngradeTrailingCommasInUnsetRector::class,
    ]);