Deprecated code still remains in file_field_tag docs.

The following example code in the docs for file_field_tag does not work because it lacks parentheses around its parameters and it uses the deprecated end_form_tag:

  <%= form_tag { :action => "post" }, { :multipart => true } %>
    <label for="file">File to Upload</label> <%= file_field_tag "file" %>
    <%= submit_tag %>
  <%= end_form_tag %>

The attached patch fixes this by evaluating the "form_tag" instead of outputting it, and removes the "end_form_tag":

 <% form_tag '/upload', :multipart => true do %>
  <label for="file">File to Upload</label> <%= file_field_tag "file" %>
  <%= submit_tag %>
 <% end %>