Fixed #20263 -- Corrected wording in the formset documentation.

Thanks to feraudyh at yahoo.com for the report.

docs/topics/forms/formsets.txt

@@ -5,7 +5,7 @@ Formsets
 
 .. class:: django.forms.formset.BaseFormSet
 
-A formset is a layer of abstraction to working with multiple forms on the same
+A formset is a layer of abstraction to work with multiple forms on the same
 page. It can be best compared to a data grid. Let's say you have the following
 form::