nixos/alloy: automaticlly include all .alloy files in reload trigger (#388634)

nixos/modules/services/monitoring/alloy.nix

@@ -30,12 +30,10 @@ in
         configuration file via `environment.etc."alloy/config.alloy"`.
 
         This allows config reload, contrary to specifying a store path.
-        A `reloadTrigger` for `config.alloy` is configured.
 
-        Other `*.alloy` files in the same directory (ignoring subdirs) are also
-        honored, but it's necessary to manually extend
-        `systemd.services.alloy.reloadTriggers` to enable config reload
-        during nixos-rebuild switch.
+        All `.alloy` files in the same directory (ignoring subdirs) are also
+        honored and are added to `systemd.services.alloy.reloadTriggers` to
+        enable config reload during nixos-rebuild switch.
 
         This can also point to another directory containing `*.alloy` files, or
         a single Alloy file in the Nix store (at the cost of reload).
@@ -68,7 +66,9 @@ in
   config = lib.mkIf cfg.enable {
     systemd.services.alloy = {
       wantedBy = [ "multi-user.target" ];
-      reloadTriggers = [ config.environment.etc."alloy/config.alloy".source or null ];
+      reloadTriggers = lib.mapAttrsToList (_: v: v.source or null) (
+        lib.filterAttrs (n: _: lib.hasPrefix "alloy/" n && lib.hasSuffix ".alloy" n) config.environment.etc
+      );
       serviceConfig = {
         Restart = "always";
         DynamicUser = true;