automated: Update flake.lock

- The following Nix Flake inputs were updated:

```
• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/3e3afe5174c561dee0df6f2c2b2236990146329f?narHash=sha256-frdhQvPbmDYaScPFiCnfdh3B/Vh81Uuoo0w5TkWmmjU%3D' (2025-06-07)
  → 'github:NixOS/nixpkgs/94def634a20494ee057c76998843c015909d6311?narHash=sha256-K2ViRJfdVGE8tpJejs8Qpvvejks1%2BA4GQej/lBk5y7I%3D' (2025-07-31)
```

Auto-generated by [update.yml][1] with the help of
[create-pull-request][2].

[1]: https://forgejo.stefka.eu/jiriks74/nix.nvim/src/branch/main/.github/workflows/update.yml
[2]: https://forgejo.stefka.eu/jiriks74/create-pull-request

flake.lock

@@ -163,11 +163,11 @@
     },
     "nixpkgs_2": {
       "locked": {
-        "lastModified": 1749285348,
+        "lastModified": 1753939845,
-        "narHash": "sha256-frdhQvPbmDYaScPFiCnfdh3B/Vh81Uuoo0w5TkWmmjU=",
+        "narHash": "sha256-K2ViRJfdVGE8tpJejs8Qpvvejks1+A4GQej/lBk5y7I=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "3e3afe5174c561dee0df6f2c2b2236990146329f",
+        "rev": "94def634a20494ee057c76998843c015909d6311",
         "type": "github"
       },
       "original": {