team-list.nix: nixos-modules -> module-system

The module system isn't about NixOS, so for consistent messaging,
I'd like to rename this.

If some of you would like to be in a team responsible for NixOS'
_use_ of the module system, that would be great, but for consistency
it should be a separate team.

Note that this attribute isn't used anywhere - only generically at
release time for the status update pings.

maintainers/team-list.nix

@@ -649,15 +649,15 @@ with lib.maintainers; {
     enableFeatureFreezePing = true;
   };
 
-  nixos-modules = {
+  module-system = {
     members = [
       ericson2314
       infinisil
       qyliss
       roberth
     ];
-    scope = "Maintain nixpkgs module system internals.";
-    shortName = "NixOS Modules / internals";
+    scope = "Maintain Nixpkgs module system";
+    shortName = "Module system";
     enableFeatureFreezePing = true;
   };