docs: Update merge function

Updates for #7601

content/en/functions/merge.md

@@ -7,13 +7,16 @@ menu:
   docs:
     parent: "functions"
 keywords: [dictionary]
-signature: ["$params :=  merge $default_params $user_params"]
+signature: ["collections.Merge MAP MAP...", "merge MAP MAP..."]
 workson: []
 hugoversion: "0.56.0"
 relatedfuncs: [dict, append, reflect.IsMap, reflect.IsSlice]
 aliases: []
 ---
 
+Merge creates a copy of the final `MAP` and merges any preceeding `MAP` into it in reverse order.
+Key handling is case-insensitive.
+
 An example merging two maps.
 
 ```go-html-template