nix-interop: fix option completion of `types.attrsOf (types.submodule…

… {})`

a.k.a. fix a small typo.

Because the type-name `attrsOf` was never matched, e.g.
`systemd.services` always had type `any`.

crates/nix-interop/src/nixos_options.nix

@@ -104,8 +104,8 @@ let
 
  listOf = { name = "list"; inherit elem; };
 
- attrOf = { name = "attrset"; rest = elem; };
- lazyAttrOf = { name = "attrset"; rest = elem; };
+ attrsOf = { name = "attrset"; rest = elem; };
+ lazyAttrsOf = { name = "attrset"; rest = elem; };
 
  uniq = elem;
  unique = elem;