This fix is not perfect, in that it will not fix every terminal that has
automargin support, but it fixes the *vast* majority of them by eliminating
the hacky workaround for the automargin - essentially using the rmam capability
to disable automatic wrapping at the margin.
I have rerun gen.sh having pulled the latest tcell to include this PR:
https://github.com/gdamore/tcell/pull/325.
I am using Ubuntu 19.04 - running gen.sh changed more fields than just
those impacted by the above fix. I've removed those from this commit. (I
verified that gen.sh changed those fields I've removed without the fix
above, so it's not related). Based on TERMINALS.md, I suspect you
regenerate these typically on a Debian machine(?)
