nixos-infect crashes with a nix syntax error on scaleway instances

[vikrem]

1. Add some ssh keys to your scaleway account
2. Start a fresh instance on scaleway. I'm using an AMP2 instance with Debian 12, but it likely doesn't matter.
3. Ssh into the machine and run nixos infect: curl https://raw.githubusercontent.com/elitak/nixos-infect/master/nixos-infect | bash -x
4. Get this error and the script crashes:

+ NIXOS_CONFIG=/etc/nixos/configuration.nix                                                                                                              
+ nix-env --set -I nixpkgs=/root/.nix-defexpr/channels/nixos -f '<nixpkgs/nixos>' -p /nix/var/nix/profiles/system -A system                              
error:                                                                                                                                                   
       … while evaluating the attribute 'config.system.build.toplevel'                                                                                   
                                                                                                                                                         
         at /nix/store/s7ml3rrzrkifc5ajrjdrf9i2ncacds8k-nixos-22.11/nixos/lib/modules.nix:346:9:                                                         
                                                                                                                                                         
          345|         options = checked options;                                                                                                        
          346|         config = checked (removeAttrs config [ "_module" ]);                                                                              
             |         ^                                                                                                                                 
          347|         _module = checked (config._module);                                                                                               
                                                                                                                                                         
       … while calling the 'seq' builtin                                                                                                                 
                                                                                                                                                         
         at /nix/store/s7ml3rrzrkifc5ajrjdrf9i2ncacds8k-nixos-22.11/nixos/lib/modules.nix:346:18:                                                        
                                                                                                                                                         
          345|         options = checked options;                                                                                                        
          346|         config = checked (removeAttrs config [ "_module" ]);                                                                              
             |                  ^                                                                                                                        
          347|         _module = checked (config._module);                                                                                               
                                                                                                                                                         
       (stack trace truncated; use '--show-trace' to show the full trace)                                                                                
                                                                                                                                                         
       error: syntax error, unexpected end of file, expecting IND_STR or DOLLAR_CURLY or IND_STRING_CLOSE                                                
                                                                                                                                                         
       at /etc/nixos/configuration.nix:34:69:                                                                                                            
                                                                                                                                                         
           33|     ''ssh-ed25519 [redacted]''                        
           34|     ''# Below your custom ssh keys from '/root/.ssh/instance_keys'''                                                                      
             |                                                                     ^                                                                     
           35|   ];         

This happens because scaleway's default /root/.ssh/authorized_keys file ends with this line:
# Below your custom ssh keys from '/root/.ssh/instance_keys'

Which ends with a single quote.
When it's copied into the nixos configuration.nix, a triple-single-quote is placed at the end of the string literal for the ssh keyfile, which breaks the configuration script.

You can work around this by deleting /etc/nixos/configuration.nix, removing the offending line at the end of /root/.ssh/authorized_keys, and running the infection script again.