nixos/installation-device.nix: improve comment about ssh login

root is not the only user that can login (user "nixos" can too), so
generalize the wording.

Changed files
+2 -2
nixos
modules
+2 -2
nixos/modules/profiles/installation-device.nix
···
start the graphical user interface.
'';
-
# We run sshd by default. Login via root is only possible after adding a
-
# password via "passwd" or by adding a ssh key to /home/nixos/.ssh/authorized_keys.
+
# We run sshd by default. Login is only possible after adding a
+
# password via "passwd" or by adding a ssh key to ~/.ssh/authorized_keys.
# The latter one is particular useful if keys are manually added to
# installation device for head-less systems i.e. arm boards by manually
# mounting the storage in a different system.