Documentation: Aliases not covered in the API documentation

[moof]

Aliases of the type:

#twisted/mail/POP3.py line 745
from twisted.mail.pop3client import POP3Client as AdvancedPOP3Client

are not covered in the API documentation. This is confusing when you're told to
use AdvancedPOP3Client by a DeprecationWarning, but this sort of thing may well
be happenning elsewhere, and it'd be useful to have a clue where some obejcts
come from sometimes.

[exarkun]

This sounds like an epydoc problem.  AdvancedPOP3Client is in
twisted.mail.pop3's __all__, so the documentation for it should end up on
twisted.mail.pop3's page.

[glyph]

Ugh.  Epydoc doesn't look like it's being maintained any more.  Should we start
a fork?

[exarkun]

This is a duplicate of #38.