flake.lock: Update

Flake lock file updates:

• Updated input 'neovim-nightly':
    'github:nix-community/neovim-nightly-overlay/8a11d160b76ea8dc76ac3356140010e38fef0ab5?narHash=sha256-fohNScp0mg8eUugIoqcLhy7tnUJ7CxhcVomizNqj5b8%3D' (2025-01-25)
  → 'github:nix-community/neovim-nightly-overlay/76c58ab72d04df8ba83357c2df3c2842371c8356?narHash=sha256-WM5sSMwECm3Q88yj79dIk8KfiXuwq1Q3GHO1DPGFIyE%3D' (2025-01-26)
• Updated input 'neovim-nightly/neovim-src':
    'github:neovim/neovim/c6d2cbf8f51abfa0c9d244ef384a15b0b69e16c6?narHash=sha256-7bgefXUOc5AVXSZ4E%2B0YzJKW4c%2BtDj1ttmDoZN1BhPs%3D' (2025-01-24)
  → 'github:neovim/neovim/b8e947ed4ed04f9aeef471f579451bbf2bb2993d?narHash=sha256-HQQ9g1jbh2KcVXiubxBpTS8P%2BKgTMVFbGPgGnXYtTSI%3D' (2025-01-25)
• Updated input 'nixpkgs':
    'github:nixos/nixpkgs/ecd26a469ac56357fd333946a99086e992452b6a?narHash=sha256-ET91TMkab3PmOZnqiJQYOtSGvSTvGeHoegAv4zcTefM%3D' (2025-01-24)
  → 'github:nixos/nixpkgs/5d3221fd57cc442a1a522a15eb5f58230f45a304?narHash=sha256-H%2BFXIKj//kmFHTTW4DFeOjR7F1z2/3eb2iwN6Me4YZk%3D' (2025-01-26)