Docs: Fix backwards default value for wp_list_users()::exclude_admin.

This was previosly listed as defaulting to `false` when in fact it defaults to `true.`

Developed in: #11022
Discussed in: https://core.trac.wordpress.org/ticket/64224
Reported in: WordPress/Documentation-Issue-Tracker#1849

Props dmsnell, noruzzaman, vHeemstra, westonruter.
See #64224.


git-svn-id: https://develop.svn.wordpress.org/trunk@61735 602fd350-edb4-49c9-b593-d223f7449a82

Author: dmsnell

src/wp-includes/user.php

@@ -894,7 +894,7 @@ function get_users( $args = array() ) {
  *                                 'display_name', 'post_count', 'ID', 'meta_value', 'user_login'. Default 'name'.
  *     @type string $order         Sorting direction for $orderby. Accepts 'ASC', 'DESC'. Default 'ASC'.
  *     @type int    $number        Maximum users to return or display. Default empty (all users).
- *     @type bool   $exclude_admin Whether to exclude the 'admin' account, if it exists. Default false.
+ *     @type bool   $exclude_admin Whether to exclude the 'admin' account, if it exists. Default true.
  *     @type bool   $show_fullname Whether to show the user's full name. Default false.
  *     @type string $feed          If not empty, show a link to the user's feed and use this text as the alt
  *                                 parameter of the link. Default empty.