Fixed #14619 -- corrected a typo in the email docs.

The ``'locmem'`` backend stores messages in a special attribute of the

``django.core.mail`` module. The ``outbox`` attribute is created when the

first message is send. It's a list with an

first message is sent. It's a list with an

:class:`~django.core.mail.EmailMessage` instance for each message that would

be send.