site: upgrade document missing the inline table of contents

[jpeach]

On the upgrade page, https://projectcontour.io/resources/upgrading/, there is supposed to be a page table of contents on the top left. If you render this using make site-devel it is there, but on the public site, it just renders as an empty div box.

[sunjayBhatia]

Not seeing the table of contents with make site-devel or the public site 👀

[sunjayBhatia]

looks like a missing <div id="toc" class="navigation"></div> (though that being on the top right takes up quite a bit of space/looks unwieldy

[sunjayBhatia]

Looks like https://github.com/projectcontour/contour/pull/3179 didn't actually fix the issue on the live site, though it did fix my local dev rendering

[a-mccarthy]

It looks like this is because the upgrade page is inheriting the page layout instead of the docs layout. For example, docs pages inherit the docs layout, https://raw.githubusercontent.com/projectcontour/contour/main/site/content/docs/main/_index.md but the upgrade page uses the page layout in the frontmatter, https://raw.githubusercontent.com/projectcontour/contour/main/site/content/resources/upgrading.md.

Since this page is also a versioned page, we should also consider moving it from the /resources folder to the docs/main folder.

Layouts: docs - https://github.com/projectcontour/contour/blob/main/site/themes/contour/layouts/_default/docs.html and page - https://github.com/projectcontour/contour/blob/main/site/themes/contour/layouts/_default/page.html