Improve some wp-admin/includes/class-wp-filesystem-*.php docs for @param.

See #30799.


git-svn-id: https://develop.svn.wordpress.org/trunk@30978 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/includes/class-wp-posts-list-table.php

@@ -429,7 +429,7 @@ class WP_Posts_List_Table extends WP_List_Table {
 	 * @param array $pages
 	 * @param int $pagenum
 	 * @param int $per_page
-	 * @return bool|null
+	 * @return false|null
 	 */
 	private function _display_rows_hierarchical( $pages, $pagenum = 1, $per_page = 20 ) {
 		global $wpdb;