Twenty Twenty-One: Use a more specific link for Dark Mode instructions.

Make both instances of the link translatable, for consistency.

Props engahmeds3ed, justinahinon.
Merges [49798] to the 5.6 branch.
Fixes #52010.

git-svn-id: https://develop.svn.wordpress.org/branches/5.6@49819 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-content/themes/twentytwentyone/classes/class-twenty-twenty-one-customize-notice-control.php

@@ -39,7 +39,7 @@ class Twenty_Twenty_One_Customize_Notice_Control extends WP_Customize_Control {
 		?>
 		<div class="notice notice-warning">
 			<p><?php esc_html_e( 'To access the Dark Mode settings, select a light background color.', 'twentytwentyone' ); ?></p>
-			<p><a href="https://wordpress.org/support/article/twenty-twenty-one/">
+			<p><a href="<?php echo esc_url( __( 'https://wordpress.org/support/article/twenty-twenty-one/#dark-mode-support', 'twentytwentyone' ) ); ?>">
 				<?php esc_html_e( 'Learn more about Dark Mode.', 'twentytwentyone' ); ?>
 			</a></p>
 		</div>

src/wp-content/themes/twentytwentyone/classes/class-twenty-twenty-one-dark-mode.php

@@ -184,9 +184,9 @@ class Twenty_Twenty_One_Dark_Mode {
 
 		$description  = '<p>';
 		$description .= sprintf(
-			// translators: %s is the wordpress.org Twenty Twenty-One support article URL.
+			/* translators: %s: Twenty Twenty-One support article URL. */
 			__( 'Dark Mode is a device setting. If a visitor to your site requests it, your site will be shown with a dark background and light text. <a href="%s">Learn more about Dark Mode.</a>', 'twentytwentyone' ),
-			__( 'https://wordpress.org/support/article/twenty-twenty-one/', 'twentytwentyone' )
+			esc_url( __( 'https://wordpress.org/support/article/twenty-twenty-one/#dark-mode-support', 'twentytwentyone' ) )
 		);
 		$description .= '</p>';
 		$description .= '<p>' . __( 'Dark Mode can also be turned on and off with a button that you can find in the bottom right corner of the page.', 'twentytwentyone' ) . '</p>';