searchable: refactor searchable_includes.

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

app/models/wiki_page_version.rb

@@ -7,7 +7,7 @@ class WikiPageVersion < ApplicationRecord
 
   module SearchMethods
     def search(params)
-      q = search_attributes(params, :id, :created_at, :updated_at, :title, :body, :other_names, :is_locked, :is_deleted)
+      q = search_attributes(params, :id, :created_at, :updated_at, :title, :body, :other_names, :is_locked, :is_deleted, :updater, :wiki_page, :artist, :tag)
       q = q.text_attribute_matches(:title, params[:title_matches])
       q = q.text_attribute_matches(:body, params[:body_matches])
 
@@ -75,10 +75,6 @@ class WikiPageVersion < ApplicationRecord
     end
   end
 
-  def self.searchable_includes
-    [:updater, :wiki_page, :artist, :tag]
-  end
-
   def self.available_includes
     [:updater, :wiki_page, :artist, :tag]
   end