eza: use mkDefault for aliases

Using `mkDefault` for the individual aliases makes it easier to
override or replace individual entries by the user, without having to
use `mkForce` which is often confusing for new users.

modules/programs/eza.nix

@@ -75,7 +75,7 @@ with lib;
 
     optionsAlias = { eza = "eza ${args}"; };
 
-    aliases = {
+    aliases = builtins.mapAttrs (_name: value: lib.mkDefault value) {
       ls = "eza";
       ll = "eza -l";
       la = "eza -a";