The tmux terminfo extensions Ss and Se are currently specified as
booleans in `st.info`. They should be strings. See
https://github.com/tmux/tmux/blob/eeedb43ae847a0a692ceea965f7556e84bca4fd0/tty-term.c
lines 254 and 265.
I have used the values from
https://invisible-island.net/ncurses/terminfo.src.html#toc-_S_I_M_P_L_E_T_E_R_M
for this patch.
