flake.lock: Update

Flake lock file updates:

• Updated input 'fenix':
    'github:nix-community/fenix/aaeaf4574767a0f5ed1787e990139aefcf4db103' (2024-03-30)
  → 'github:nix-community/fenix/055f6db376eaf544d84aa55bd5a7c70634af41ba' (2024-04-27)
• Updated input 'fenix/rust-analyzer-src':
    'github:rust-lang/rust-analyzer/f5a9250147f6569d8d89334dc9cca79c0322729f' (2024-03-29)
  → 'github:rust-lang/rust-analyzer/1ed7e2de05ee76f6ae83cc9c72eb0b33ad6903f2' (2024-04-26)
• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/807c549feabce7eddbf259dbdcec9e0600a0660d' (2024-03-29)
  → 'github:NixOS/nixpkgs/d6f6eb2a984f2ba9a366c31e4d36d65465683450' (2024-04-27)