Slim SEO: Add total page number to the meta title for paginated pages

filter.php

<?php
add_filter( 'slim_seo_data', 'change_pagination_text' );
add_filter( 'document_title_parts', 'change_pagination_text' );

function change_pagination_text( $data ) {
	if ( ! is_paged() ) {
		return $data;
	}

	global $wp_query;
	$paged = get_query_var( 'paged' );
	$data['page'] = 'Page ' . $paged . ' of ' . $wp_query->max_num_pages;

	return $data;
}