Proper heading for admin screens.

First step towards restoring a good heading structure in wp-admin.
The previous `<h1>` contained the site title and a link to the front page and was removed with the toolbar refactoring in 3.2.

Props joedolson, afercia.
Fixes #31650.


Built from https://develop.svn.wordpress.org/trunk@32974


git-svn-id: http://core.svn.wordpress.org/trunk@32945 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/tools.php

@@ -33,7 +33,7 @@ require_once( ABSPATH . 'wp-admin/admin-header.php' );
 
 ?>
 <div class="wrap">
-<h2><?php echo esc_html( $title ); ?></h2>
+<h1><?php echo esc_html( $title ); ?></h1>
 
 <?php if ( current_user_can('edit_posts') ) : ?>
 <div class="card pressthis">