nixos/vim: update example of package option

Closes https://github.com/NixOS/nixpkgs/pull/403998

Co-authored-by: Hans Kristian Eiken <hans@eikjen.no>
Co-authored-by: Lin Jian <me@linj.tech>
Signed-off-by: John Titor <50095635+JohnRTitor@users.noreply.github.com>

nixos/modules/programs/vim.nix

@@ -14,7 +14,7 @@ in
 
     defaultEditor = lib.mkEnableOption "vim as the default editor";
 
-    package = lib.mkPackageOption pkgs "vim" { example = "vim-full"; };
+    package = lib.mkPackageOption pkgs "vim" { example = [ "vim-full" ]; };
   };
 
   # TODO: convert it into assert after 24.11 release