hugo/docs/layouts/shortcodes/gh.html

{{ range .Params }}
{{   if eq (substr . 0 1) "@" }}
<a href="//github.com/{{ substr . 1 }}">{{ . }}</a>
{{   else if eq (substr . 0 2) "0x" }}
<a href="//github.com/spf13/hugo/commit/{{ substr . 2 }}">{{ substr . 2 6 }}</a>
{{   else }}
<a href="//github.com/spf13/hugo/issues/{{ . }}">#{{ . }}</a>
{{   end }}
{{ end }}