Fixed a typo.

Author: apollo13

docs/ref/utils.txt

@@ -529,7 +529,7 @@ escaping HTML.
 
  .. code-block:: python
 
- format_html(u"%{0} <b>{1}</b> {2}",
+ format_html(u"{0} <b>{1}</b> {2}",
  mark_safe(some_html), some_text, some_other_text)
 
  This has the advantage that you don't need to apply :func:`escape` to each