symlink(2) is a very dumb syscall, and allows you to put any damn value
you please inside a symlink. In addition, spaces are valid path
characters which causes issues with keyword parsing. So use Vis() and
Unvis() to safely store an encoded version of the path.
This also adds a cli test for this behaviour.
Signed-off-by: Aleksa Sarai <asarai@suse.de>