add category hints from methodlist

ccp/js/methodlistcontroller.js

@@ -200,7 +200,7 @@ class CCPMethodList extends HTMLElement{
       if(this.#data === null) return [];
       for(let i=0; i < this.#data.length; i++){
         const cat = this.#data[i].metadata.filter(md=>md.role === "category").map(md=>md.title)
-        s.add(cat)
+        cat.forEach(c=>s.add(c))
       }
       return [...s]
     }