Twenty Twenty: Revert usage of str_contains() in theme files.

The theme supports WordPress 4.7 or later, while the polyfill for `str_contains()` only exists in WordPress 5.9 or later.

Follow-up to [55988], [57275].

Props poena.
See #60241.

git-svn-id: https://develop.svn.wordpress.org/trunk@57276 602fd350-edb4-49c9-b593-d223f7449a82

Author: SergeyBiryukov

src/wp-content/themes/twentytwenty/comments.php

@@ -80,7 +80,7 @@
 				$pagination_classes = '';
 
 				// If we're only showing the "Next" link, add a class indicating so.
-				if ( ! str_contains( $comment_pagination, 'prev page-numbers' ) ) {
+				if ( false === strpos( $comment_pagination, 'prev page-numbers' ) ) {
 					$pagination_classes = ' only-next';
 				}
 				?>

src/wp-content/themes/twentytwenty/functions.php

@@ -323,7 +323,7 @@ function twentytwenty_get_custom_logo( $html ) {
 			);
 
 			// Add a style attribute with the height, or append the height to the style attribute if the style attribute already exists.
-			if ( ! str_contains( $html, ' style=' ) ) {
+			if ( false === strpos( $html, ' style=' ) ) {
 				$search[]  = '/(src=)/';
 				$replace[] = "style=\"height: {$logo_height}px;\" src=";
 			} else {

src/wp-content/themes/twentytwenty/template-parts/pagination.php

@@ -37,12 +37,12 @@
 );
 
 // If we're not outputting the previous page link, prepend a placeholder with `visibility: hidden` to take its place.
-if ( ! str_contains( $posts_pagination, 'prev page-numbers' ) ) {
+if ( false === strpos( $posts_pagination, 'prev page-numbers' ) ) {
 	$posts_pagination = str_replace( '<div class="nav-links">', '<div class="nav-links"><span class="prev page-numbers placeholder" aria-hidden="true">' . $prev_text . '</span>', $posts_pagination );
 }
 
 // If we're not outputting the next page link, append a placeholder with `visibility: hidden` to take its place.
-if ( ! str_contains( $posts_pagination, 'next page-numbers' ) ) {
+if ( false === strpos( $posts_pagination, 'next page-numbers' ) ) {
 	$posts_pagination = str_replace( '</div>', '<span class="next page-numbers placeholder" aria-hidden="true">' . $next_text . '</span></div>', $posts_pagination );
 }