docs: fix factory method name

Author: kenjis

user_guide_src/source/database/utilities/004.php

@@ -1,6 +1,6 @@
 <?php
 
-$dbutil = \CodeIgniter\Database\Config::utils();
+$dbutil = \Config\Database::utils();
 
 $dbs = $dbutil->listDatabases();
 

user_guide_src/source/database/utilities/006.php

@@ -1,6 +1,6 @@
 <?php
 
-$dbutil = \CodeIgniter\Database\Config::utils();
+$dbutil = \Config\Database::utils();
 
 if ($dbutil->optimizeTable('table_name')) {
     echo 'Success!';

user_guide_src/source/database/utilities/010.php

@@ -1,7 +1,7 @@
 <?php
 
 $db     = db_connect();
-$dbutil = \CodeIgniter\Database\Config::utils();
+$dbutil = \Config\Database::utils();
 
 $query = $db->query('SELECT * FROM mytable');