docs: Prepare for new sub tree

See #11925

docs/content/en/functions/collections/KeyVals.md

@@ -1,43 +0,0 @@
----
-title: collections.KeyVals
-description: Returns a KeyVals struct.
-categories: []
-keywords: []
-action:
-  aliases: [keyVals]
-  related:
-    - methods/pages/Related
-  returnType: types.KeyValues
-  signatures: [collections.KeyVals KEY VALUES...]
-aliases: [/functions/keyvals]
----
-
-The primary application for this function is the definition of the `namedSlices` parameter in the options map passed to the [`Related`] method on the `Pages` object.
-
-[`Related`]: /methods/pages/related
-
-See [related content](/content-management/related).
-
-```go-html-template
-{{ $kv := keyVals "foo" "a" "b" "c" }}
-```
-
-The resulting data structure is:
-
-```json
-{
-  "Key": "foo",
-  "Values": [
-    "a",
-    "b",
-    "c"
-  ]
-}
-```
-
-To extract the key and values:
-
-```go-html-template
-{{ $kv.Key }} → foo
-{{ $kv.Values }} → [a b c]
-```