fix(packages/zenergy): remove package from flake and explain how to use it

flake.nix

@@ -74,7 +74,6 @@
 
       packages."${system}" = {
         wb32dfu-udev-rules = pkgs.callPackage ./packages/wb32dfu-udev-rules { };
-        zenergy = pkgs.callPackage ./packages/zenergy.nix { };
       };
 
       nixosModules = {

packages/README.md

@@ -4,6 +4,13 @@ This is a kernel driver that adds the ability for user to fetch power draw data
 [nixpkgs], so you shouldn't use this package _unless_ it is broken in your current
 version of [nixpkgs].
 
+Unfortunately this cannot be outputted as a package in the flake since to create a derivation the `kernel` parameter
+must be present, which, each user will have their own kernel package.
+
+Thus you need to copy the `zenergy.nix` file somewhere in your configuration and inside `boot.extraModulePackages` pass
+the package with the following expression: `config.boot.kernelPackages.callPackage ./path/to/zenergy.nix`; successfully
+installing the package onto your system.
+
 ## wb32dfu-udev-rules
 
 This package installs the udev rules necessary to allow flashing QMK/Vial onto keyboards that use WB32-DFU bootloaders.