nixos/redis: fix evaluation

Commit 89fee1006c03d40052842b49f5cdbbeb755d081b ("nixos/redis: clean up
option types") broke nixos evaluation:

  error: attempt to call something which is not a function but a set, at .../nixpkgs/nixos/modules/services/databases/redis.nix:111:28

Fix it.

Reported by Oliver Charles (thanks!).

1 files changed, 1 insertions, 1 deletions

diff --git a/nixos/modules/services/databases/redis.nix b/nixos/modules/services/databases/redis.nix
index db6b0813ff9b..b91c389e90a2 100644
--- a/nixos/modules/services/databases/redis.nix
+++ b/nixos/modules/services/databases/redis.nix
@@ -108,7 +108,7 @@ in
       };
 
       save = mkOption {
-        type = with types; listOf listOf int;
+        type = with types; listOf (listOf int);
         default = [ [900 1] [300 10] [60 10000] ];
         description = "The schedule in which data is persisted to disk, represented as a list of lists where the first element represent the amount of seconds and the second the number of changes.";
         example = [ [900 1] [300 10] [60 10000] ];