Add customised 'read more' links to hand crafted excerpts

functions.php

<?php

// Add "Read More" link to hand-crafted excerpts
add_filter('get_the_excerpt', 'wpm_manual_excerpt_read_more_link');
function wpm_manual_excerpt_read_more_link($excerpt) {
    $excerpt_more = '';
    if (has_excerpt() && ! is_attachment() && get_post_type() == 'post') {
        $excerpt_more = '&nbsp;<a href="' . get_permalink() . '">[Continue&nbsp;reading] <span class="screen-reader-text">' . get_the_title() . '</span></a>';
    }
    return $excerpt . $excerpt_more;
}