Install shell completions in Nix Flake (kamiyaa#421)

* update `flake.lock`

Flake lock file updates:

• Updated input 'devenv':
    'github:cachix/devenv/8d6d129b666778538b76bcb069ab82f813094e5c' (2023-05-30)
  → 'github:cachix/devenv/3654eb5d47218cfa2d12280ba5ac1ace0a9dd225' (2023-08-30)
• Updated input 'devenv/pre-commit-hooks':
    'github:cachix/pre-commit-hooks.nix/fb58866e20af98779017134319b5663b8215d912' (2023-04-27)
  → 'github:cachix/pre-commit-hooks.nix/5843cf069272d92b60c3ed9e55b7a8989c01d4c7' (2023-06-29)
• Updated input 'devenv/pre-commit-hooks/flake-utils':
    'github:numtide/flake-utils/5aed5285a952e0b949eb3ba02c12fa4fcfef535f' (2022-11-02)
  → 'github:numtide/flake-utils/a1720a10a6cfe8234c0e93907ffe81be440f4cef' (2023-05-31)
• Added input 'devenv/pre-commit-hooks/flake-utils/systems':
    'github:nix-systems/default/da67096a3b9bf56a91d16901293e51ba5b49a27e' (2023-04-09)
• Updated input 'devenv/pre-commit-hooks/nixpkgs-stable':
    'github:NixOS/nixpkgs/9b8e5abb18324c7fe9f07cb100c3cd4a29cda8b8' (2023-03-15)
  → 'github:NixOS/nixpkgs/c37ca420157f4abc31e26f436c1145f8951ff373' (2023-06-03)
• Updated input 'fenix':
    'github:nix-community/fenix/9ea56d5de762971f6a7319711bae0532ca454dc9' (2023-05-30)
  → 'github:nix-community/fenix/76e468cd74a08edcbabb14ce1698ebd2f5fad9d2' (2023-08-29)
• Updated input 'fenix/rust-analyzer-src':
    'github:rust-lang/rust-analyzer/bc8295255c5bcc293251d47590dcbfd320eaab87' (2023-05-29)
  → 'github:rust-lang/rust-analyzer/62268e474e9165de0cdb08d3794eec4b6ef1c6cd' (2023-08-28)
• Updated input 'flake-parts':
    'github:hercules-ci/flake-parts/80717d11615b6f42d1ad2e18ead51193fc15de69' (2023-05-30)
  → 'github:hercules-ci/flake-parts/59cf3f1447cfc75087e7273b04b31e689a8599fb' (2023-08-01)
• Updated input 'flake-parts/nixpkgs-lib':
    'github:NixOS/nixpkgs/da45bf6ec7bbcc5d1e14d3795c025199f28e0de0?dir=lib' (2023-04-30)
  → 'github:NixOS/nixpkgs/9e1960bc196baf6881340d53dccb203a951745a2?dir=lib' (2023-08-01)
• Updated input 'flake-root':
    'github:srid/flake-root/f1c0b93d05bdbea6c011136ba1a135c80c5b326c' (2023-04-08)
  → 'github:srid/flake-root/d9a70d9c7a5fd7f3258ccf48da9335e9b47c3937' (2023-08-22)
• Updated input 'mission-control':
    'github:Platonic-Systems/mission-control/a0c93bd764a3c25e6999397e9f5f119c1b124e38' (2023-05-09)
  → 'github:Platonic-Systems/mission-control/9d25d9f8d610916fc144f6afc1f064392fbeec1c' (2023-07-28)
• Updated input 'nix2container':
    'github:nlewo/nix2container/2e0a633344489b3171afe136b820b4602f9d1807' (2023-05-16)
  → 'github:nlewo/nix2container/ab381a7d714ebf96a83882264245dbd34f0a7ec8' (2023-07-09)
• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/5e871d8aa6f57cc8e0dc087d1c5013f6e212b4ce' (2023-05-29)
  → 'github:NixOS/nixpkgs/3efb0f6f404ec8dae31bdb1a9b17705ce0d6986e' (2023-08-28)
• Updated input 'treefmt-nix':
    'github:numtide/treefmt-nix/3d352b2b1a46164443aa114bd29d8d208d8a9bd0' (2023-05-30)
  → 'github:numtide/treefmt-nix/6befd3b6b8544952e0261f054cf16769294bacba' (2023-08-28)
• Updated input 'treefmt-nix/nixpkgs':
    'github:nixos/nixpkgs/d9f759f2ea8d265d974a6e1259bd510ac5844c5d' (2023-04-08)
  → 'github:nixos/nixpkgs/ce5e4a6ef2e59d89a971bc434ca8ca222b9c7f5e' (2023-08-10)

* install shell completions in `Nix Flake`

* add GitHub Actions workflow for checking `Nix Flake`

.github/workflows/nix.yaml

@@ -0,0 +1,24 @@
+name: "Nix Flakes"
+
+on:
+  push:
+    branches: [dev, main]
+
+  pull_request:
+    branches: [dev, main]
+
+jobs:
+  build-nix-flake:
+    name: Build Nix Flake
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Install Nix
+        uses: cachix/install-nix-action@v22
+
+      - name: Build Nix Flake
+        run: nix build
+
+      - name: Test executable
+        run: ./result/bin/joshuto version

nix/default.nix

@@ -1,6 +1,7 @@
 { lib
 , stdenv
 , rustPlatform
+, installShellFiles
 , darwin
 , version ? "git"
 }:
@@ -22,6 +23,15 @@ rustPlatform.buildRustPackage rec {
     darwin.apple_sdk.frameworks.Foundation
   ];
 
+  nativeBuildInputs = [ installShellFiles ];
+
+  postInstall = ''
+    installShellCompletion --cmd joshuto \
+      --bash <($out/bin/joshuto completions bash) \
+      --zsh <($out/bin/joshuto completions zsh) \
+      --fish <($out/bin/joshuto completions fish)
+  '';
+
   patchPhase = ''
     sed -i 's/env!("CARGO_PKG_VERSION")/\"${version}\"/g' src/main.rs
   '';