List tables: Account for comments being reused on the post edit screen.

Adding the `.wp-list-table` class gets us a few responsive goodies for free. And now it won't show a strange button outline.

see #32395.

Built from https://develop.svn.wordpress.org/trunk@33101


git-svn-id: http://core.svn.wordpress.org/trunk@33072 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/includes/class-wp-comments-list-table.php

@@ -747,6 +747,7 @@ class WP_Post_Comments_List_Table extends WP_Comments_List_Table {
 	 */
 	protected function get_table_classes() {
 		$classes = parent::get_table_classes();
+		$classes[] = 'wp-list-table';
 		$classes[] = 'comments-box';
 		return $classes;
 	}