Add some debugging information to be able to customise the prebuild/not
cases for this script.
Also, handle `zsh-autosuggestions` not being available for Ubuntu 18.04.
- My Codespaces workflow sometimes involves `gh cs ssh` for a terminal
and tmux and vim (for better or for worse).
- I tried this on a `Homebrew/brew` Codespace and got this error. But it felt
weird following that instruction to the letter and bloating the Docker image
which we by default keep minimal.
```
❯ gh cs ssh
? Choose codespace: Homebrew/brew (master): redesigned spork
error getting ssh server details: failed to start server:
Please check if an SSH server is installed in the container.
If the docker image being used for the codespace does not have an SSH server,
install it in your Dockerfile or, for codespaces that use Debian-based images,
you can add the following to your devcontainer.json:
"features": {
"ghcr.io/devcontainers/features/sshd:1": {
"version": "latest"
}
}
```
