Fix tmux terminfo extensions Se and Ss

The tmux terminfo extensions Ss and Se are currently specified as
booleans in `st.info`. They should be strings. See
eeedb43ae8/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.

st.info

@@ -189,10 +189,10 @@ st| simpleterm,
 	rmxx=\E[29m,
 	smxx=\E[9m,
 # tmux extensions, see TERMINFO EXTENSIONS in tmux(1)
-	Se,
-	Ss,
 	Tc,
 	Ms=\E]52;%p1%s;%p2%s\007,
+	Se=\E[2 q,
+	Ss=\E[%p1%d q,
 
 st-256color| simpleterm with 256 colors,
 	use=st,