Change behavior of categories in search results

src/invidious/search.cr

@@ -231,11 +231,16 @@ def process_search_query(url_params, query, page, user, region)
     count, items = search(search_query, search_params, region).as(Tuple)
   end
 
-  # Light processing to ignore extracted items from categories for now.
-  # They should ideally be supported in the frontend in the future
+  # Light processing to flatten search results out of Categories.
+  # They should ideally be supported in the future.
   items_without_cate_items = [] of SearchItem | ChannelVideo
   items.each do |i|
     if i.is_a? Category
+      i.contents.each do |nest_i|
+        if !nest_i.is_a? Video
+          items_without_cate_items << nest_i
+        end
+      end
     else
       items_without_cate_items << i
     end