bug#61393: Guix System's PS1 does not set the terminal title

[Maxim Cournoyer]

Hi,

The tabs in GNOME's Console (kgx command) are blanks (no names).  This
appears to be due to not having a title set via an ANSI escape in our
default prompt (PS1 environment variable).

We should look at what Fedora is using and extend our PS1 with it.

To confirm that it works, type the following in Console:

--8<---------------cut here---------------start------------->8---
echo -e "\033]0;[title]\07"
--8<---------------cut here---------------end--------------->8---

And you'll see the tab becomes named "[title]".

-- 
Thanks,
Maxim