screenfetch: Fix hostname, display the actual shell

It displayed empty hostname when the scheme of the current working directory was not the file:/ scheme.
Also the shell is not guaranteed to be Ion.
3 jobs for screenfetch in 47 seconds
Status Job ID Name Coverage
  Build
failed #9051
build

00:00:47

 
  Test
skipped #9053
allowed to fail
code_quality
skipped #9052
test
 
Name Stage Failure
failed
build Build
Checking out 1f6cbe1c as screenfetch...
Skipping Git submodules setup
$ # Auto DevOps variables and functions # collapsed multi-line command
$ setup_docker
$ build
Logging to GitLab Container Registry with CI credentials...
WARNING! Using --password via the CLI is insecure. Use --password-stdin.
Get https://registry-1.docker.io/v2/: unauthorized: incorrect username or password
ERROR: Job failed: exit code 1