added some docs to shut PhpStorm up

src/pocketmine/Server.php

@@ -2156,6 +2156,10 @@ class Server{
 		}
 	}
 
+	/**
+	 * @param \Throwable $e
+	 * @param array|null $trace
+	 */
 	public function exceptionHandler(\Throwable $e, $trace = null){
 		if($e === null){
 			return;