Documentation for simply_helpful features rolled into rails 2

Hi All,

In Ryan B. screencast episode 80 (Ruby on Rails Screencasts - RailsCasts
80) on simplifying views in rails he mentions that

<% render :partial =>‘product’ , :collection => @products %> and <%
render :partial =>‘product’ , :object => @product %>

can now be written as

<%= render :partial => @products %> and <%= render :partial =>
@product %> respectively.

He also says that <%form_for :product, :url → products_path do |f|
%> and <%form_for :product, :url =>product_path(@product), :html =>
{:method => ‘put’} do |f| %>

can now both be written

<% form_for @product do |f| %>

Can anyone tell me where this is documented since the api only
mentions the old ways as far as I can see unless I am looking in the
wrong place.

Many thanks