docs: Fix simple typo, similiar -> similar
docs: Fix simple typo, similiar -> similar

There is a small typo in paypal/standard/pdt/admin.py.

Should read `similar` rather than `similiar`.

rsalmaso/django-paypal,spookylukey/django-paypal,spookylukey/django-paypal,spookylukey/django-paypal,rsalmaso/django-paypal,rsalmaso/django-paypal