[Ruleset Engine] The len() function supports arrays (#19606)

src/content/docs/ruleset-engine/rules-language/functions.mdx

@@ -135,11 +135,11 @@ For example, if `http.request.uri.path` is `"/welcome.html"`, then `ends_with(ht
 ### `len`
 
 {/* prettier-ignore */}
-<code>len(<Type text="String | Bytes" />)</code>: <Type text="Integer" />
+<code>len(<Type text="String | Bytes | Array" />)</code>: <Type text="Integer" />
 
-Returns the byte length of a String or Bytes field.
+Returns the byte length of a String or Bytes value, or the number of elements in an array.
 
-For example, if `http.host` is `"example.com"`, then `len(http.host)` will return `11`.
+For example, if the value of `http.host` is `"example.com"`, then `len(http.host)` will return `11`.
 
 ### `lookup_json_integer`
 
@@ -348,7 +348,7 @@ url_decode("%2520", "r")   will return " "
 // Using url_decode() with the any() function:
 any(url_decode(http.request.body.form.values[*])[*] contains "an xss attack")
 
-// Using the u option to match a specific alphabet 
+// Using the u option to match a specific alphabet
 url_decode(http.request.uri.path) matches "(?u)\p{Hangul}+"
 ```