This will affect many pages (e.g., everywhere we show an example path such as layouts/_default/single.html, directory tree structures, etc.), so we may want to start with just the lookup order page to reduce merge conflicts with the changes for #2996.

Need to review:

• Reimplement and simplify Hugo's template system hugo#13541
• Add new standard layout 'all' (in addition to single,list) hugo#13545
• Deprecate the _internal/some-template construct hugo#13553

Also:

• Revise inline partial examples too: https://gohugo.io/templates/partial/#inline-partials
• Need to change URLs to embedded templates (shortcodes, render hooks, etc.). See data/embedded_template_urls.toml. This is addressed in #2992.
• Check override instructions (the template path) for alias.html, robots.txt, rss.xml, sitemap.xml, and sitemapindex.xml.
• Document partial naming. See this comment, which is a bit confusing: tpl: Fix language handling in partials hugo#13614 (comment)