Changes
convert this to use Module:Ns has subpages - this gets the subpage status directly from MediaWiki, avoiding the need to update the template when namespaces change
{{ {{{|<includeonly>safesubst:}}}</includeonly>#switch: {{ {{{|safesubst:}}}NAMESPACE: {{{1|{{ {{{|safesubst:}}}FULLPAGENAME}}}}}:Foo }} |{{ {{{|safesubst:}}}ns:0}} |{{ {{{|safesubst:}}}ns:File}} |{{ {{{|safesubst:}}}ns:MediaWiki}} |{{ {{{|safesubst:}}}nsinvoke:Category}} = Ns has subpages|yesmain}}<noinclude>
{{documentation}}
<!-- Categories go on the /doc subpage and interwikis go on Wikidata. -->
</noinclude>
