less: allow customization

Signed-off-by: Pamplemousse <xav.maso@gmail.com>

tests/modules/programs/less/default.nix

@@ -0,0 +1 @@
+{ less-with-custom-keys = ./less-with-custom-keys.nix; }

tests/modules/programs/less/less-with-custom-keys.nix

@@ -0,0 +1,26 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+{
+  programs.less = {
+    enable = true;
+
+    keys = ''
+      s        back-line
+      t        forw-line
+    '';
+  };
+
+  test.stubs.less = { };
+
+  nmt.script = ''
+    assertFileExists home-files/.lesskey
+    assertFileContent home-files/.lesskey ${
+      builtins.toFile "less.expected" ''
+        s        back-line
+        t        forw-line
+      ''
+    }
+  '';
+}