fox: 1.6.49 -> 1.6.56

Semi-automatic update generated by https://github.com/ryantm/nix-update tools. These checks were done:

- built on NixOS
- ran `/nix/store/84izmk7vawbjy8jq443ym0wx7k2a89my-fox-1.6.56/bin/reswrap -h` got 0 exit code
- ran `/nix/store/84izmk7vawbjy8jq443ym0wx7k2a89my-fox-1.6.56/bin/reswrap --help` got 0 exit code
- ran `/nix/store/84izmk7vawbjy8jq443ym0wx7k2a89my-fox-1.6.56/bin/adie -h` got 0 exit code
- ran `/nix/store/84izmk7vawbjy8jq443ym0wx7k2a89my-fox-1.6.56/bin/adie --help` got 0 exit code
- ran `/nix/store/84izmk7vawbjy8jq443ym0wx7k2a89my-fox-1.6.56/bin/fox-config --version` and found version 1.6.56
- found 1.6.56 with grep in /nix/store/84izmk7vawbjy8jq443ym0wx7k2a89my-fox-1.6.56
- directory tree listing: https://gist.github.com/04085b0f58d3548a56ff6ed257520c45