Refactor searching text attributes.

* Allow using ApplicationRecord#attribute_matches to search text attributes,
and standardize models on using this instead of duplicating code.

* Remove restrictions that limited wildcard searches to Builders only in various places.

app/models/comment.rb

@@ -27,14 +27,6 @@ class Comment < ApplicationRecord
       reorder("comments.id desc").limit(6)
     end
 
-    def body_matches(query)
-      if query =~ /\*/ && CurrentUser.user.is_builder?
-        where("body ILIKE ? ESCAPE E'\\\\'", query.to_escaped_for_sql_like)
-      else
-        where("body_index @@ plainto_tsquery(?)", query.to_escaped_for_tsquery_split).order("comments.id DESC")
-      end
-    end
-
     def hidden(user)
       if user.is_moderator?
         where("(score < ? and is_sticky = false) or is_deleted = true", user.comment_threshold)
@@ -74,9 +66,7 @@ class Comment < ApplicationRecord
     def search(params)
       q = super
 
-      if params[:body_matches].present?
-        q = q.body_matches(params[:body_matches])
-      end
+      q = q.attribute_matches(:body, params[:body_matches], index_column: :body_index)
 
       if params[:post_id].present?
         q = q.where("post_id in (?)", params[:post_id].split(",").map(&:to_i))