Rss Array Output Question

I am calling data onto my homepage using the following coding:

<?php require_once('compilations/wp-config.php'); wp_widget_rss_output(array(
    'url'           => 'https://the-compilers.com/compilations/tag/harry-lime/feed/',
    'title'         => __( 'Some Title'),
    'items'         => 10,
    'show_summary'  => 0,
    'show_author'   => 0,
    'show_date'     => 0
));

?>

This is working well but i would like to limit the amount of letters used in the item title and wasn’t sure which array to use to achieve this.

Any ideas would be welcome?