docs: Prepare for new sub tree

See #11925

docs/content/en/methods/menu-entry/URL.md

@@ -1,23 +0,0 @@
----
-title: URL
-description: Returns the relative permalink of the page associated with the given menu entry, else its `url` property.
-categories: []
-keywords: []
-action:
-  related: []
-  returnType: string
-  signatures: [MENUENTRY.URL]
----
-
-For menu entries associated with a page, the `URL` method returns the page's [`RelPermalink`], otherwise it returns the entry's `url` property.
-
-
-```go-html-template
-<ul>
-  {{ range .Site.Menus.main }}
-    <li><a href="{{ .URL }}">{{ .Name }}</a></li>
-  {{ end }}
-</ul>
-```
-
-[`RelPermalink`]: /methods/page/relpermalink