nix/module.nix: refactor comments

modules/system/nix/module.nix

@@ -26,24 +26,22 @@ in {
       lib.mapAttrs (_: v: {flake = v;}) inputs
       // {system.flake = inputs.self;};
 
-    # This will additionally add your inputs to the system's legacy channels
-    # Making legacy nix commands consistent as well
+    # Add inputs to the system's legacy channels
+    # to make legacy nix commands consistent as well
     nixPath = mapAttrsToList (key: _: "${key}=flake:${key}") config.nix.registry;
 
-    # Run the Nix daemon on lowest possible priority so that my system
-    # stays responsive during demanding tasks such as GC and builds.
-    # This is especially useful while auto-gc and auto-upgrade are enabled
-    # as they can be quite demanding on the CPU.
+    # Run the Nix daemon on lowest possible priority
     daemonCPUSchedPolicy = "idle";
     daemonIOSchedClass = "idle";
     daemonIOSchedPriority = 7;
 
     # Collect garbage
+    # NOTE: I use nh for this.
     gc = {
       automatic = false;
       dates = "20:00";
       options = "--delete-older-than 7d";
-      persistent = false; # don't try to catch up on missed GC runs
+      persistent = false;
     };
 
     # Automatically optimize nix store by removing hard links
@@ -132,13 +130,12 @@ in {
       keep-derivations = true;
       keep-outputs = true;
 
-      # Use binary cache, this is not Gentoo
-      # external builders can also pick up those substituters
+      # Use binary cache
       builders-use-substitutes = true;
 
       # Substituters to pull from.
       substituters = [
-        "https://cache.nixos.org" # funny binary cache
+        "https://cache.nixos.org"
       ];
 
       trusted-public-keys = [