docs: Prepare for new sub tree

See #11925

docs/content/en/functions/strings/RuneCount.md

@@ -1,24 +0,0 @@
----
-title: strings.RuneCount
-description: Returns the number of runes in the given string.
-categories: []
-keywords: []
-action:
-  aliases: []
-  related:
-    - functions/go-template/len
-    - functions/strings/Count
-    - functions/strings/CountRunes
-    - functions/strings/CountWords
-  returnType: int
-  signatures: [strings.RuneCount INPUT]
-aliases: [/functions/strings.runecount]
----
-
-In contrast with the [`strings.CountRunes`] function, which excludes whitespace, `strings.RuneCount` counts every rune in a string.
-
-```go-html-template
-{{ "Hello, 世界" | strings.RuneCount }} → 9
-```
-
-[`strings.CountRunes`]: /functions/strings/countrunes