some channels make the ui scroll a bit

[cblgh]

 12:31:30 <rtn> for some reason, some channels make the ui scroll a bit (cli version)
 12:31:49 <rtn> the top row cabal@version disappears

18:03:09 <@kira> yes, I think what happens is that some line is
                writing more than process.stdout.columns, which
                terminals wrap, which cascades down the ui output
                until an extra line gets written to the very bottom,
                which induces terminal scroll, pushing the entire UI
                up
18:04:03 <@kira> you can also reproduce it by writing a chat message
                draft at the bottom that is longer than one line --
                it'll scroll the entire ui

maybe related to #186