riseup.net: include domain into the username

[link2xt]

I have checked by configuring testing account
manually with username being a full email
instead of just the local part.

This is how it is specified in
https://autoconfig.riseup.net/mail/config-v1.1.xml

I also tested manually with openssl-s_client
that IMAP server at mail.riseup.net:993 accepts username
both with and without the domain name.
Domain name is however not ignored,
it is impossible to login as "user@example.org"
if your email address is "user@riseup.net",
but using just "user" is fine.

[link2xt]

I am looking through providers using EMAILLOCALPART login type. This seems to be not a common option. In case of disroot.org they specify that they want local part, but actually accept login with any domain appended afterwards or even user@@@@. Looks like everything after @ including @ is just ignored. iCloud has the weirdest setup where IMAP expects only local part, but SMTP expects domain name as well: https://support.apple.com/en-us/102525

In any case for riseup.net it makes sense to use "official" configuration. For disroot I am not going to switch to full address even though it seems to work, because it is not documented.