[php-src] Issue #18878: DOMDocument::saveHTML() adds additional symbols before some UTF-8 characters in HTML

Issue: https://github.com/php/php-src/issues/18878 Author: MurzNN ### Description The following code: ```php <?php $html='<p>My Brand®</p>'; $dom = new \DOMDocument(); $dom->encoding = 'UTF-8'; $dom->loadHTML($html, LIBXML_HTML_NOIMPLIED | LIBXML_HTML_NODEFDTD); $result = $dom->saveHTML(); print($result); ``` Resulted in this output: ``` <p>My Brand&Acirc;&reg;</p> ``` But I expected this output instead: ``` <p>My Brand®</p> ``` Or at least this: ``` <p>My Brand&reg;</p> ``` The same issue is with other unicode characters, eg this: ```php $html='<p>My ☆ Brand</p>'; ``` output: ``` <p>My &acirc;&#152;&#134; Brand</p> ``` Could you please explain why this happens, and how to fix this issue? Or maybe any workarounds? ### PHP Version ```plain PHP 8.4.5 (cli) (built: Mar 17 2025 20:35:32) (NTS) Copyright (c) The PHP Group Zend Engine v4.4.5, Copyright (c) Zend Technologies with Zend OPcache v8.4.5, Copyright (c), by Zend Technologies ``` ### Operating System Ubuntu 25.04