searchable: refactor searchable_includes.

Pass searchable associations directly to search_attributes instead of
defining them separately in searchable_includes.

app/models/post_appeal.rb

@@ -17,7 +17,7 @@ class PostAppeal < ApplicationRecord
 
   module SearchMethods
     def search(params)
-      q = search_attributes(params, :id, :created_at, :updated_at, :reason, :status)
+      q = search_attributes(params, :id, :created_at, :updated_at, :reason, :status, :creator, :post)
       q = q.text_attribute_matches(:reason, params[:reason_matches])
 
       q.apply_default_order(params)
@@ -34,10 +34,6 @@ class PostAppeal < ApplicationRecord
     errors.add(:post, "cannot be appealed") if post.is_status_locked? || !post.is_appealable?
   end
 
-  def self.searchable_includes
-    [:creator, :post]
-  end
-
   def self.available_includes
     [:creator, :post]
   end