clarified instructions for using display_override hook
http://codeigniter.com/bug_tracker/bug/4512/
diff --git a/user_guide/general/hooks.html b/user_guide/general/hooks.html
index 5cd361f..60bdf02 100644
--- a/user_guide/general/hooks.html
+++ b/user_guide/general/hooks.html
@@ -140,7 +140,7 @@
Called immediately after your controller is fully executed.</li>
<li><strong>display_override</strong><br />
Overrides the <dfn>_display()</dfn> function, used to send the finalized page to the web browser at the end of system execution. This permits you to
- use your own display methodology. Note that the finalized data will be available by calling <dfn>$this->output->get_output()</dfn></li>
+ use your own display methodology. Note that you will need to reference the CI superobject with <dfn>$this->CI =& get_instance()</dfn> and then the finalized data will be available by calling <dfn>$this->CI->output->get_output()</dfn></li>
<li><strong>cache_override</strong><br />
Enables you to call your own function instead of the <dfn>_display_cache()</dfn> function in the output class. This permits you to use your own cache display mechanism.</li>
<li><strong>scaffolding_override</strong><br />