Fix #1898: Include alias predicates in non-empty Tags search.

Make searches on the /tags index includes aliases too. Show matching
aliases like this:

   Name: gray*

   ? 75098 grey_hair <- gray_hair
   ? 35345 grey_eyes <- gray_eyes

app/controllers/tags_controller.rb

@@ -10,6 +10,7 @@ class TagsController < ApplicationController
 
   def index
     @tags = Tag.paginated_search(params)
+    @tags = @tags.includes(:consequent_aliases) if request.format.html?
     respond_with(@tags)
   end