[Toybox] hexedit uses VT-420 scroll ctrl sequences which dont work on tty1

[Jarno Mäkipää]

Hey

I was looking at how should I limit unchanged lines being rewritten
every keypress in vi editor.
So I look reference in hexedit and noticed that it does not work
properly on virtual terminals
(one that open with ctrl+alt+f1...)

hexedit seems to use esc[1S and esc[1T for scrolling and found them in here

https://invisible-island.net/xterm/ctlseqs/ctlseqs.html

CSI Ps S  Scroll up Ps lines (default = 1) (SU), VT420, ECMA-48.
CSI Ps T  Scroll down Ps lines (default = 1) (SD), VT420.

While most of the time its not really issue, since people run X or
have ssh/telnet or serial connection from other device with proper
terminal emulator. But in those rare case when you have keyboard and
framebuffer console and just messed up that one byte in your file it
might come handy to be able fix it.

Is there any easy way checking if terminal currently running supports
these? Or should I just ignore and use them anyway, perhaps have :set
something to disable them?

br
-Jarno