docs(skills): remove temporary nix let example

src/skills/nix-style/rules/let.md

@@ -14,43 +14,3 @@ Do not make an output attrset recursive only to reference sibling outputs.
 Shared convenience bindings hide dependency direction.
 Explicit references show which value owns a concept and which value consumes it.
 
-### Examples
-
-Prefer:
-
-```nix
-formatter.${system} = (import ./formatter.nix {
-  inherit inputs system;
-}).config.build.wrapper;
-
-apps.${system} = import ./apps.nix {
-  inherit
-    inputs
-    lib
-    system
-    ;
-  formatter = self.formatter.${system};
-};
-```
-
-Avoid:
-
-```nix
-let
-  formatter = import ./formatter.nix {
-    inherit inputs system;
-  };
-in
-{
-  formatter.${system} = formatter.config.build.wrapper;
-
-  apps.${system} = import ./apps.nix {
-    inherit
-      inputs
-      lib
-      formatter
-      system
-      ;
-  };
-}
-```