add `treefmt` and `pre-commit-hooks`

I can now run `nix fmt` or `nix flake check` to check the syntax for
various files in this repository.

Fixed a deprecation warning for `hugo`:
```
> WARN  The author key in site configuration is deprecated. Use params.author.email instead.
> WARN  The author key in site configuration is deprecated. Use params.author.name instead.
```

1 files changed, 161 insertions, 1 deletions

diff --git a/flake.lock b/flake.lock
index 2dc3d82..677ddcb 100644
--- a/flake.lock
+++ b/flake.lock
@@ -1,5 +1,21 @@
 {
   "nodes": {
+    "flake-compat": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1673956053,
+        "narHash": "sha256-4gtG9iQuiKITOjNQQeQIpoIB6b16fm+504Ch3sNKLd8=",
+        "owner": "edolstra",
+        "repo": "flake-compat",
+        "rev": "35bb57c0c8d8b62bbfd284272c928ceb64ddbde9",
+        "type": "github"
+      },
+      "original": {
+        "owner": "edolstra",
+        "repo": "flake-compat",
+        "type": "github"
+      }
+    },
     "flake-utils": {
       "inputs": {
         "systems": "systems"
@@ -18,6 +34,45 @@
         "type": "github"
       }
     },
+    "flake-utils_2": {
+      "inputs": {
+        "systems": "systems_2"
+      },
+      "locked": {
+        "lastModified": 1685518550,
+        "narHash": "sha256-o2d0KcvaXzTrPRIo0kOLV0/QXHhDQ5DTi+OxcjO8xqY=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "a1720a10a6cfe8234c0e93907ffe81be440f4cef",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "gitignore": {
+      "inputs": {
+        "nixpkgs": [
+          "pre-commit-hooks",
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1660459072,
+        "narHash": "sha256-8DFJjXG8zqoONA1vXtgeKXy68KdJL5UaXR8NtVMUbx8=",
+        "owner": "hercules-ci",
+        "repo": "gitignore.nix",
+        "rev": "a20de23b925fd8264fd7fad6454652e142fd7f73",
+        "type": "github"
+      },
+      "original": {
+        "owner": "hercules-ci",
+        "repo": "gitignore.nix",
+        "type": "github"
+      }
+    },
     "nixpkgs": {
       "locked": {
         "lastModified": 1701624383,
@@ -34,10 +89,82 @@
         "type": "github"
       }
     },
+    "nixpkgs-stable": {
+      "locked": {
+        "lastModified": 1685801374,
+        "narHash": "sha256-otaSUoFEMM+LjBI1XL/xGB5ao6IwnZOXc47qhIgJe8U=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "c37ca420157f4abc31e26f436c1145f8951ff373",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-23.05",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs_2": {
+      "locked": {
+        "lastModified": 1689261696,
+        "narHash": "sha256-LzfUtFs9MQRvIoQ3MfgSuipBVMXslMPH/vZ+nM40LkA=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "df1eee2aa65052a18121ed4971081576b25d6b5c",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs_3": {
+      "locked": {
+        "lastModified": 1695644571,
+        "narHash": "sha256-asS9dCCdlt1lPq0DLwkVBbVoEKuEuz+Zi3DG7pR/RxA=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "6500b4580c2a1f3d0f980d32d285739d8e156d92",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "pre-commit-hooks": {
+      "inputs": {
+        "flake-compat": "flake-compat",
+        "flake-utils": "flake-utils_2",
+        "gitignore": "gitignore",
+        "nixpkgs": "nixpkgs_2",
+        "nixpkgs-stable": "nixpkgs-stable"
+      },
+      "locked": {
+        "lastModified": 1700922917,
+        "narHash": "sha256-ej2fch/T584b5K9sk1UhmZF7W6wEfDHuoUYpFN8dtvM=",
+        "owner": "cachix",
+        "repo": "pre-commit-hooks.nix",
+        "rev": "e5ee5c5f3844550c01d2131096c7271cec5e9b78",
+        "type": "github"
+      },
+      "original": {
+        "owner": "cachix",
+        "repo": "pre-commit-hooks.nix",
+        "type": "github"
+      }
+    },
     "root": {
       "inputs": {
         "flake-utils": "flake-utils",
-        "nixpkgs": "nixpkgs"
+        "nixpkgs": "nixpkgs",
+        "pre-commit-hooks": "pre-commit-hooks",
+        "treefmt-nix": "treefmt-nix"
       }
     },
     "systems": {
@@ -54,6 +181,39 @@
         "repo": "default",
         "type": "github"
       }
+    },
+    "systems_2": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    },
+    "treefmt-nix": {
+      "inputs": {
+        "nixpkgs": "nixpkgs_3"
+      },
+      "locked": {
+        "lastModified": 1699786194,
+        "narHash": "sha256-3h3EH1FXQkIeAuzaWB+nK0XK54uSD46pp+dMD3gAcB4=",
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "rev": "e82f32aa7f06bbbd56d7b12186d555223dc399d1",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "type": "github"
+      }
     }
   },
   "root": "root",