docs: Prepare for new sub tree

See #11925

docs/content/en/functions/path/Ext.md

@@ -1,24 +0,0 @@
----
-title: path.Ext
-description: Replaces path separators with slashes (`/`) and returns the file name extension of the given path.
-categories: []
-keywords: []
-action:
-  aliases: []
-  related:
-    - functions/path/Base
-    - functions/path/BaseName
-    - functions/path/Clean
-    - functions/path/Dir
-    - functions/path/Join
-    - functions/path/Split
-  returnType: string
-  signatures: [path.Ext PATH]
-aliases: [/functions/path.ext]
----
-
-The extension is the suffix beginning at the final dot in the final slash-separated element of path; it is empty if there is no dot.
-
-```go-html-template
-{{ path.Ext "a/b/c/news.html" }} → .html
-```