POP3 support - either implement or remove from description

Submitted by mpan-tmp-6da33dd1

Assigned to Xfce-Goodies Maintainers

Link to original bug (#10615)

Description

Despite plugin documentation suggests that there is POP3 support, there is actually none. The implementation just reports number of e-mails in the inbox.

Please either implement the feature or remove information about it from the descripton. Currently the documentation is misleading.