Sitemap rules not respected for multilingual documentations

[Vultik]

Hi, According to Google documentation, each language variation should be put with <xhtml:link> including the default language.

Current Sitemap:

    <url>
        <loc>https://super_doc.com/fr/index.html</loc>
        <xhtml:link rel="alternate" hreflang="en" href="https://super_doc.com/en/index.html" />
    </url>

Expected Sitemap:

    <url>
        <loc>https://super_doc.com/fr/index.html</loc>
        <xhtml:link rel="alternate" hreflang="en" href="https://super_doc.com/en/index.html" />
        <xhtml:link rel="alternate" hreflang="fr" href="https://super_doc.com/fr/index.html" />
    </url>

https://developers.google.com/search/docs/advanced/crawling/localized-versions#sitemap