Create a shortcode with your code layout/shortcodes/sitemap.html
(I modified the code):
<ul>
{{ range site.RegularPages }}
<li><a href="{{ .RelPermalink }}">{{ .Title }}</a></li>
{{ end }}
</ul>
Then create your sitemap page content/sitemap.md
and insert the shortcode:
+++
title = "Sitemap"
+++
All the pages of my great site:
{{< sitemap >}}
And the text continues ;)