Changes
adding a second argument: default "all" but you can put in "pages" or "subcats" etc. as documented on mw:Help:Magic_words#Statistics and it passes it through to the magic word
[[:Category:{{{1}}}]] ({{PAGESINCATEGORY:{{{1}}}|{{{2|all}}}}})<noinclude>
[[Category:Internal category-link templates]]
</noinclude>
[[Category:Internal category-link templates]]
</noinclude>