flake.lock: Update (#347)

Flake lock file updates:

• Updated input 'neovim-nightly':
    'github:nix-community/neovim-nightly-overlay/f751e2e0c00a9393410361b205f42658611ae89b?narHash=sha256-PULZxwVju7sX7YTDiu2Gr15htFEEoMJ95ZZ6FGj%2Bqa0%3D' (2024-09-06)
  → 'github:nix-community/neovim-nightly-overlay/3861fe1b245a758cf08952025c70904f7a7e5403?narHash=sha256-GDrsqGI4T0TeSt9kQWvUynmF8g0H2yfW/HOxpA4euIk%3D' (2024-09-07)
• Updated input 'neovim-nightly/neovim-src':
    'github:neovim/neovim/9570ad24f52442d75d677412cfe2fa83a7ff7a88?narHash=sha256-sRezYqvmEjS/TIumXiwIN%2BttuEPhNNtDnUY7wCpSCAs%3D' (2024-09-05)
  → 'github:neovim/neovim/738a84de09a053a01e9fc167722aed36cc782a1f?narHash=sha256-MAuFtcFoNkvIbCzU2x5X1DsYGgn22blT1LGuPxreMKE%3D' (2024-09-06)
• Updated input 'neovim-nightly/nixpkgs':
    'github:NixOS/nixpkgs/fcb54ddcc974cff59bdfb7c1ac9e080299763d2d?narHash=sha256-hd1eRyPtTkRnAPYpnEfzugQwAifVYMmOR3z%2BMTTSw%2Bg%3D' (2024-09-05)
  → 'github:NixOS/nixpkgs/9bb1e7571aadf31ddb4af77fc64b2d59580f9a39?narHash=sha256-Yd0FK9SkWy%2BZPuNqUgmVPXokxDgMJoGuNpMEtkfcf84%3D' (2024-09-05)

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>