Change the output using filter??

I’m trying to change the output of this plugin using add_filter in function.php
I want to put each popular post inside a link instead of li
I also need to add an “eye icon” which is represented by <span data-icon=””></span> before views count, but I can’t get it to work, help please

function wpp_custom_html_views($output){
$output = str_replace(‘<p>’,'<p><span data-icon=””></span>’,$output);
return $output;
}
add_filter(‘wpp_custom_html’, ‘wpp_custom_html_views’);

https://wordpress.org/plugins/wordpress-popular-posts/