docs: Prepare for new sub tree

See #11925

docs/content/en/functions/safe/HTML.md

@@ -1,39 +0,0 @@
----
-title: safe.HTML
-description: Declares the given string as a safeHTML string.
-categories: []
-keywords: []
-action:
-  aliases: [safeHTML]
-  related:
-    - functions/safe/CSS
-    - functions/safe/HTMLAttr
-    - functions/safe/JS
-    - functions/safe/JSStr
-    - functions/safe/URL
-  returnType: template.HTML
-  signatures: [safe.HTML INPUT]
-aliases: [/functions/safehtml]
----
-
-It should not be used for HTML from a third-party, or HTML with unclosed tags or comments.
-
-Given a site-wide [`hugo.toml`][config] with the following `copyright` value:
-
-{{< code-toggle file=hugo >}}
-copyright = "© 2015 Jane Doe.  <a href=\"https://creativecommons.org/licenses/by/4.0/\">Some rights reserved</a>."
-{{< /code-toggle >}}
-
-`{{ .Site.Copyright | safeHTML }}` in a template would then output:
-
-```html
-© 2015 Jane Doe.  <a href="https://creativecommons.org/licenses/by/4.0/">Some rights reserved</a>.
-```
-
-However, without the `safeHTML` function, html/template assumes `.Site.Copyright` to be unsafe and therefore escapes all HTML tags and renders the whole string as plain text:
-
-```html
-<p>© 2015 Jane Doe.  &lt;a href=&#34;https://creativecommons.org/licenses by/4.0/&#34;&gt;Some rights reserved&lt;/a&gt;.</p>
-```
-
-[config]: /getting-started/configuration/