Issue: https://github.com/php/php-src/issues/20374
Author: franck-paul
### Description
The following code:
```php
<?php
$str = '<custom-html-element>test</custom-html-element>';
$config = [
'custom-tags' => 'blocklevel',
];
$tidy = new \tidy();
$tidy->parseString($str, $config, 'utf8');
$tidy->cleanRepair();
$str = (string) $tidy->value;
var_dump($str); // should be <custom-html-element>test</custom-html-element>
```
Resulted in this output:
```
test
```
But I expected this output instead:
```
<custom-html-element>test</custom-html-element>
```
### PHP Version
```plain
PHP 8.4.14 (cli) (built: Oct 21 2025 19:23:55) (NTS)
Copyright (c) The PHP Group
Built by Homebrew
Zend Engine v4.4.14, Copyright (c) Zend Technologies
with Zend OPcache v8.4.14, Copyright (c), by Zend Technologies
with Xdebug v3.4.0, Copyright (c) 2002-2024, by Derick Rethans
```
### Operating System
MacOS