Twenty Twenty One: Fix post navigation to respect sort order.

Change the labels on post navigation links when the sort order is changed so the labels accurately reflect the target entries.

Previously, if the sort order was reversed, 'Older' or 'Previous' links would navigate to newer entries and 'Newer' or 'Next' links would navigate to older entries.

Props jikamens, dancameron, obenland, shrey0shrivastava, sirlouen, sabernhardt, shailu25, joedolson.
See #10219.

git-svn-id: https://develop.svn.wordpress.org/trunk@61091 602fd350-edb4-49c9-b593-d223f7449a82

Author: joedolson

src/wp-content/themes/twentytwentyone/inc/template-tags.php

@@ -219,6 +219,10 @@ function twenty_twenty_one_post_thumbnail() {
 	 * @return void
 	 */
 	function twenty_twenty_one_the_posts_navigation() {
+		$order          = get_query_var( 'order', 'DESC' );
+		$new_posts_text = __( 'Newer <span class="nav-short">posts</span>', 'twentytwentyone' );
+		$old_posts_text = __( 'Older <span class="nav-short">posts</span>', 'twentytwentyone' );
+
 		the_posts_pagination(
 			array(
 				'before_page_number' => esc_html__( 'Page', 'twentytwentyone' ) . ' ',
@@ -227,7 +231,7 @@ function twenty_twenty_one_the_posts_navigation() {
 					'%s <span class="nav-prev-text">%s</span>',
 					is_rtl() ? twenty_twenty_one_get_icon_svg( 'ui', 'arrow_right' ) : twenty_twenty_one_get_icon_svg( 'ui', 'arrow_left' ),
 					wp_kses(
-						__( 'Newer <span class="nav-short">posts</span>', 'twentytwentyone' ),
+						( 'DESC' === $order ) ? $new_posts_text : $old_posts_text,
 						array(
 							'span' => array(
 								'class' => array(),
@@ -238,7 +242,7 @@ function twenty_twenty_one_the_posts_navigation() {
 				'next_text'          => sprintf(
 					'<span class="nav-next-text">%s</span> %s',
 					wp_kses(
-						__( 'Older <span class="nav-short">posts</span>', 'twentytwentyone' ),
+						( 'DESC' === $order ) ? $old_posts_text : $new_posts_text,
 						array(
 							'span' => array(
 								'class' => array(),