Add ellipsis [...] on the post archive

/**
 * Theme's overridden of excerpt function
 */
function astra_the_excerpt() {

    $excerpt_type = apply_filters( 'astra_excerpt_type', astra_get_option( 'blog-post-content' ) );

    do_action( 'astra_the_excerpt_before', $excerpt_type );
    ?>
        <div class="ast-excerpt-container ast-blog-single-element">
            <?php
            if ( 'full-content' === $excerpt_type ) {
                the_content();
            } else {
                the_excerpt();
            }
            ?>
        </div>
    <?php

    do_action( 'astra_the_excerpt_after', $excerpt_type );
}

/**
 * Filter to change the excerpt more string to dots ...
 */
add_filter( 'excerpt_more', 'extended_excerpt_more' );
function extended_excerpt_more( $more ) {
    return '[...]';
}