Fixed #12505 -- Clarified the use of the extra argument in formsets. Thanks to...

    <tr><th><label for="id_form-0-title">Title:</label></th><td><input type="text" name="form-0-title" id="id_form-0-title" /></td></tr>

    <tr><th><label for="id_form-0-pub_date">Pub date:</label></th><td><input type="text" name="form-0-pub_date" id="id_form-0-pub_date" /></td></tr>

As you can see it only displayed one form. This is because by default the

``formset_factory`` defines one extra form. This can be controlled with the

``extra`` parameter::

As you can see it only displayed one empty form. The number of empty forms

that is displayed is controlled by the ``extra`` parameter. By default,

``formset_factory`` defines one extra form; the following example will

display two blank forms::

    >>> ArticleFormSet = formset_factory(ArticleForm, extra=2)