Revert "refactor(dotfiles): inline registry join"

This reverts commit 8fa11b85fd.

src/dotfiles/registry/collection.nix

@@ -59,14 +59,16 @@ let
 
   rawDeclarations =
     registryName: lib.mapAttrs (_hostName: host: host.config.registry.${registryName} or { }) hosts;
+
+  join =
+    registry: host: entry:
+    lib.filterAttrs (_name: value: value != null) (
+      lib.mapAttrs (
+        registryName: _registry: (registry.${registryName}.${host} or { }).${entry} or null
+      ) definitions
+    );
 in
 collectData
 // {
-  join =
+  join = host: entry: join collectData host entry;
-    host: entry:
-    lib.filterAttrs (_name: value: value != null) (
-      lib.mapAttrs (
-        registryName: _registry: (collectData.${registryName}.${host} or { }).${entry} or null
-      ) definitions
-    );
 }