lux-cli: install all man pages

[mrcjkb]

Things done

A future version of Lux will have more than on man page.
This PR updates the build to install all man pages.

• Built on platform:
  • x86_64-linux
  • aarch64-linux
  • aarch64-darwin
• Tested, as applicable:
  • NixOS tests in nixos/tests.
  • Package tests at passthru.tests.
  • Tests in lib/tests or pkgs/test for functions and "core" functionality.
• Ran nixpkgs-review on this PR. See nixpkgs-review usage.
• Tested basic functionality of all binary files, usually in ./result/bin/.
• Nixpkgs Release Notes
  • Package update: when the change is major or breaking.
• NixOS Release Notes
  • Module addition: when adding a new NixOS module.
  • Module update: when the change is significant.
• Fits CONTRIBUTING.md, pkgs/README.md, maintainers/README.md and other READMEs.
• Follows the automation/AI policy.

[mrcjkb]

✅ nixpkgs-review result

Generated using nixpkgs-review-gha (71d8654)

Command: nixpkgs-review pr 539752
Commit: e06abad66157e3e185e208705dcaec0c93fa9a73 (subsequent changes)
Merge: 8f43bb790674e7645cfc48094147d25781b63425

Logs: https://github.com/mrcjkb/nixpkgs-review-gha/actions/runs/28983766228/attempts/1

---

x86_64-linux

✅ 1 package built:

• lux-cli

---

aarch64-linux

✅ 1 package built:

• lux-cli

---

x86_64-darwin

✅ No rebuilds

---

aarch64-darwin (sandbox = relaxed)

✅ 1 package built:

• lux-cli