Index: wp-admin/includes/class-wp-list-table.php
===================================================================
--- wp-admin/includes/class-wp-list-table.php	(revisione 38811)
+++ wp-admin/includes/class-wp-list-table.php	(copia locale)
@@ -656,7 +656,7 @@
 
 		// No comments at all.
 		if ( ! $approved_comments && ! $pending_comments ) {
-			printf( '<span aria-hidden="true">—</span><span class="screen-reader-text">%s</span>',
+			printf( '<span aria-hidden="true">&#8212;</span><span class="screen-reader-text">%s</span>',
 				__( 'No comments' )
 			);
 		// Approved comments have different display depending on some conditions.