flake.lock: Update

Flake lock file updates:

• Updated input 'fenix':
    'github:nix-community/fenix/aaeaf4574767a0f5ed1787e990139aefcf4db103?narHash=sha256-iGb6ptUaNBOCftKnNJiWT5z1ftngfNtwqJkD8Z9Vwfw%3D' (2024-03-30)
  → 'github:nix-community/fenix/8f14b37d4ad9eafd33315ba67faded5c1e1a1044?narHash=sha256-W68/drb51fBhOl/BMOoRlI%2B7qxeoNWGmCZwAyuXVlQY%3D' (2024-09-14)
• Updated input 'fenix/rust-analyzer-src':
    'github:rust-lang/rust-analyzer/f5a9250147f6569d8d89334dc9cca79c0322729f?narHash=sha256-dyezzeSbWMpflma%2BE9USmvSxuLgGcNGcGw3cOnX36ko%3D' (2024-03-29)
  → 'github:rust-lang/rust-analyzer/4221354a8fe90ea8218d3757d14735eac08d3e81?narHash=sha256-0Cb2bK2eyZ1njSX3593USMlcrj94VZprNN1/HllIfgw%3D' (2024-09-13)
• Updated input 'nixpkgs':
    'github:nixos/nixpkgs/d8fe5e6c92d0d190646fb9f1056741a229980089?narHash=sha256-iMUFArF0WCatKK6RzfUJknjem0H9m4KgorO/p3Dopkk%3D' (2024-03-29)
  → 'github:nixos/nixpkgs/4f807e8940284ad7925ebd0a0993d2a1791acb2f?narHash=sha256-IiA3jfbR7K/B5%2B9byVi9BZGWTD4VSbWe8VLpp9B/iYk%3D' (2024-09-11)
• Updated input 'rust-overlay':
    'github:oxalica/rust-overlay/db12d0c6ef002f16998723b5dd619fa7b8997086?narHash=sha256-6eaaoJUkr4g9J/rMC4jhj3Gv8Sa62rvlpjFe3xZaSjM%3D' (2024-07-02)
  → 'github:oxalica/rust-overlay/e9f8641c92f26fd1e076e705edb12147c384171d?narHash=sha256-YfLRPlFZWrT2oRLNAoqf7G3%2BNnUTDdlIJk6tmBU7kXM%3D' (2024-09-14)