Remove use of value.bound_blocks from basic StructBlock template example.

This hasn't been necessary since #1360 was merged, and the new 'BoundBlocks and values' section covers it much better.

docs/topics/streamfield.rst

@@ -441,12 +441,10 @@ Within the template, the block value is accessible as the variable ``value``:
     <div class="person">
         {% image value.photo width-400 %}
         <h2>{{ value.first_name }} {{ value.surname }}</h2>
-        {{ value.bound_blocks.biography.render }}
+        {{ value.biography }}
     </div>
 
 
-The line ``value.bound_blocks.biography.render`` warrants further explanation. While blocks such as RichTextBlock are aware of their own rendering, the actual block *values* (as returned when accessing properties of a StructBlock, such as ``value.biography``), are just plain Python values such as strings. To access the block's proper HTML rendering, you must retrieve the 'bound block' - an object which has access to both the rendering method and the value - via the ``bound_blocks`` property.
-
 .. _streamfield_get_context:
 
 To pass additional context variables to the template, block subclasses can override the ``get_context`` method: