[1.7.x] Fixed typo in docs/topics/forms/modelforms.txt.

inner ``Meta`` class. This should be a dictionary mapping field names to widget

classes or instances.

For example, if you want the a ``CharField`` for the ``name``

attribute of ``Author`` to be represented by a ``<textarea>`` instead

of its default ``<input type="text">``, you can override the field's

widget::

For example, if you want the ``CharField`` for the ``name`` attribute of

``Author`` to be represented by a ``<textarea>`` instead of its default

``<input type="text">``, you can override the field's widget::

    from django.forms import ModelForm, Textarea

    from myapp.models import Author