chore: update flake.lock

[mrcjkb]

Automated changes by the update-flake-lock GitHub Action.

Flake lock file updates:

• Updated input 'neovim-nightly':
    'github:neovim/neovim/1f551e068f728ff38bd7fdcfa3a6daf362bab9da?dir=contrib' (2023-09-12)
  → 'github:neovim/neovim/f5953edbac14febce9d4f8a3c35bdec1eae26fbe?dir=contrib' (2023-09-13)
• Updated input 'nixpkgs':
    'github:nixos/nixpkgs/1ee50a29288f768c55211963be8040671814986d' (2023-09-12)
  → 'github:nixos/nixpkgs/1697b7d480449b01111e352021f46e5879e47643' (2023-09-13)

Running GitHub Actions on this PR

GitHub Actions will not run workflows on pull requests which are opened by a GitHub Action.

To run GitHub Actions workflows on this PR, run:

git branch -D update_flake_lock_action
git fetch origin
git checkout update_flake_lock_action
git commit --amend --no-edit
git push origin update_flake_lock_action --force