Revert accidental 5.9 branch commits [54655] and [54656]

Unprops audrasjb.
See #56867, #56792, #56862, #56792.


Built from https://develop.svn.wordpress.org/branches/5.9@54657


git-svn-id: http://core.svn.wordpress.org/branches/5.9@54209 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/includes/theme.php

@@ -442,7 +442,7 @@ function get_theme_feature_list( $api = true ) {
  * @param string       $action API action to perform: 'query_themes', 'theme_information',
  *                             'hot_tags' or 'feature_list'.
  * @param array|object $args   {
- *     Optional. Array or object of arguments to serialize for the Themes API. Default empty array.
+ *     Optional. Array or object of arguments to serialize for the Themes API.
  *
  *     @type string  $slug     The theme slug. Default empty.
  *     @type int     $per_page Number of themes per page. Default 24.

wp-trackback.php

@@ -25,7 +25,7 @@ wp_set_current_user( 0 );
  *
  * @param int|bool $error         Whether there was an error.
  *                                Default '0'. Accepts '0' or '1', true or false.
- * @param string   $error_message Error message if an error occurred. Default empty string.
+ * @param string   $error_message Error message if an error occurred.
  */
 function trackback_response( $error = 0, $error_message = '' ) {
 	header( 'Content-Type: text/xml; charset=' . get_option( 'blog_charset' ) );