[1.7.x] Fixed mistakes in docs/topics/forms/formsets.txt examples.

Backport of 9c8a2ab from master

docs/topics/forms/formsets.txt

@@ -218,6 +218,7 @@ this management data, an exception will be raised::
     ...     'form-0-pub_date': u'',
     ... }
     >>> formset = ArticleFormSet(data)
+    >>> formset.is_valid()
     Traceback (most recent call last):
     ...
     django.forms.utils.ValidationError: [u'ManagementForm data is missing or has been tampered with']
@@ -474,8 +475,7 @@ Lets you create a formset with the ability to select forms for deletion::
     ...     {'title': u'Article #2', 'pub_date': datetime.date(2008, 5, 11)},
     ... ])
     >>> for form in formset:
-    ....    print(form.as_table())
-    <input type="hidden" name="form-TOTAL_FORMS" value="3" id="id_form-TOTAL_FORMS" /><input type="hidden" name="form-INITIAL_FORMS" value="2" id="id_form-INITIAL_FORMS" /><input type="hidden" name="form-MAX_NUM_FORMS" id="id_form-MAX_NUM_FORMS" />
+    ...     print(form.as_table())
     <tr><th><label for="id_form-0-title">Title:</label></th><td><input type="text" name="form-0-title" value="Article #1" 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" value="2008-05-10" id="id_form-0-pub_date" /></td></tr>
     <tr><th><label for="id_form-0-DELETE">Delete:</label></th><td><input type="checkbox" name="form-0-DELETE" id="id_form-0-DELETE" /></td></tr>