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.



git-svn-id: https://develop.svn.wordpress.org/trunk@32974 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/import.php

@@ -52,7 +52,7 @@ $parent_file = 'tools.php';
 ?>
 
 <div class="wrap">
-<h2><?php echo esc_html( $title ); ?></h2>
+<h1><?php echo esc_html( $title ); ?></h1>
 <?php if ( ! empty( $_GET['invalid'] ) ) : ?>
 	<div class="error"><p><strong><?php _e('ERROR:')?></strong> <?php printf( __('The <strong>%s</strong> importer is invalid or is not installed.'), esc_html( $_GET['invalid'] ) ); ?></p></div>
 <?php endif; ?>