MB_CASE_TITLE treats entities as words (in contrast to uc_words)

Description

The following code:

<?php
$txt = 'acme &amp; co';

echo mb_convert_case($txt, MB_CASE_TITLE, 'UTF-8'), PHP_EOL;

Resulted in this output:

Acme &Amp; Co

But I expected this output instead:

Acme & Co

Using uc_words produces the expected result:

<?php
$txt = 'acme &amp; co';

echo ucwords($txt), PHP_EOL;

results in

Acme & Co

PHP Version

PHP 8.4.5, PHP 8.2.26

Operating System

No response

从 mb_convert_case 入口开始，使用提供的 acme & co 示例重现报告的 PHP 8.4.5 和 8.2.26 行为。当标题大小写转换保留实体为 &，同时仍生成 Acme 和 Co，并为报告的输入提供回归覆盖时，工作即完成。