Administration and Site Health: Make information on Search engine visibility more prominent.

- makes the "Search engines discouraged" message on the Dashboard more prominent
- adds "Search engine visibility" information under Site Health > Info > WordPress 
- removes title case in favor of sentence case in all the related strings 

Props audrasjb, swissspidy, emanuel_blagonic, Presskopp, karmatosed, valentinbora, melchoyce.
Fixes #35288.


git-svn-id: https://develop.svn.wordpress.org/trunk@47859 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/includes/class-wp-debug-data.php

@@ -40,6 +40,7 @@ class WP_Debug_Data {
 		$permalink_structure    = get_option( 'permalink_structure' );
 		$is_ssl                 = is_ssl();
 		$users_can_register     = get_option( 'users_can_register' );
+		$blog_public            = get_option( 'blog_public' );
 		$default_comment_status = get_option( 'default_comment_status' );
 		$is_multisite           = is_multisite();
 		$core_version           = get_bloginfo( 'version' );
@@ -103,6 +104,11 @@ class WP_Debug_Data {
 					'value' => $users_can_register ? __( 'Yes' ) : __( 'No' ),
 					'debug' => $users_can_register,
 				),
+				'blog_public'            => array(
+					'label' => __( 'Is this site discouraging search engines?' ),
+					'value' => $blog_public ? __( 'No' ) : __( 'Yes' ),
+					'debug' => $blog_public,
+				),
 				'default_comment_status' => array(
 					'label' => __( 'Default comment status' ),
 					'value' => 'open' === $default_comment_status ? _x( 'Open', 'comment status' ) : _x( 'Closed', 'comment status' ),