load matrix-lib directly inside module

To enable use with non-flakes

flake.nix

@@ -7,7 +7,7 @@
 
   outputs = { self, nixpkgs-lib }: {
     nixosModules = {
-      synapse = import ./synapse-module { matrix-lib = self.lib; };
+      synapse = import ./synapse-module;
     };
     lib = import ./lib.nix { lib = nixpkgs-lib.lib; };
   };

synapse-module/default.nix

@@ -1,5 +1,5 @@
-{ matrix-lib }:
 { pkgs, lib, config, ... }:
+{ matrix-lib ? (import ../lib.nix { inherit lib; }) }:
 let
   cfg = config.services.matrix-synapse-next;
   wcfg = cfg.workers;