starship: Re-enable containers module

Having some indicator that we're in a container is better than no
indicator at all. starship takes forever to compile, so patching it
would introduce excessively long build times.

modules/starship.nix

@@ -22,7 +22,6 @@
       };
 
       line_break.disabled = true;
-      container.disabled = true;
 
       nodejs = {
         format = "with [$symbol($version )]($style)";