地址： https://github.com/mislav/will_paginate/wiki/API-documentation
page_entries_info(collection, options)Renders a message containing number of displayed vs. total entries.
<%= page_entries_info @posts %>
#=> Displaying posts 6 - 12 of 26 in total
:model - a model class or string name (default: collection.first.class):html - set to false to generate plain text (default: true)You can customize the output format using I18n.
原文：http://www.cnblogs.com/qinyan20/p/4609370.html