Fixed another typo in templates docs.

       the ``needs_autoescape`` attribute to ``True`` on your function. (If you

       don't specify this attribute, it defaults to ``False``). This attribute

       tells Django that your filter function wants to be passed an extra

       keyword argument, called ``autoescape``, that is ``True`` is

       keyword argument, called ``autoescape``, that is ``True`` if

       auto-escaping is in effect and ``False`` otherwise.

       For example, let's write a filter that emphasizes the first character of