Templates that have some for of documentation on how to use it.

To the actual template page, add <noinclude>{{documentation}}</noinclude>, and the link to the doc page is created. from the section it's easy click and create the /doc page.

To create a proper /doc page that adds the category to the page(and links to the actual template?), you add {{documentation subpage|override=nameofthetemplate/doc|Nameofthetemplate}}, and it will show as documentation on the actual Template page.