#2829 landed on master and touched 173 of the same keys this branch
rewrites, which is where the conflicts came from.
Resolved by rule rather than by hand: for any key #2829 already fixed
and merged, master's value wins (54 keys); everything else keeps this
branch's version. That keeps the diff against master limited to what is
genuinely new here, and avoids re-editing work that is already upstream.
It also avoids a regression. This branch was cut before #2829, so it
still carried the old double-encoded UTF-8 in nine mailboxes strings
(confirm_warnallf, left_autoreply, left_folders, left_forward,
left_pass, left_sig, mail_fromfilter, mail_selread, mail_subfilter).
Taking master's value for those keeps them fixed. A mojibake scan over
the whole tree after the merge reports 0 remaining lines.
master also added acl/forgot_sudouser, which is translated here, so
lang/tr is still complete at 31,523 of 31,523 keys.
78b728a531