brltty: 5.5 -> 5.6

Semi-automatic update. These checks were performed:

- built on NixOS
- ran `/nix/store/4zz86z1wi6k5nny7wiyqngpm8d94k9r7-brltty-5.6/bin/brltty-ctb -h` got 0 exit code
- ran `/nix/store/4zz86z1wi6k5nny7wiyqngpm8d94k9r7-brltty-5.6/bin/brltty-ctb --help` got 0 exit code
- ran `/nix/store/4zz86z1wi6k5nny7wiyqngpm8d94k9r7-brltty-5.6/bin/brltty -h` got 0 exit code
- ran `/nix/store/4zz86z1wi6k5nny7wiyqngpm8d94k9r7-brltty-5.6/bin/brltty --help` got 0 exit code
- ran `/nix/store/4zz86z1wi6k5nny7wiyqngpm8d94k9r7-brltty-5.6/bin/brltty help` got 0 exit code
- ran `/nix/store/4zz86z1wi6k5nny7wiyqngpm8d94k9r7-brltty-5.6/bin/brltty -V` and found version 5.6
- ran `/nix/store/4zz86z1wi6k5nny7wiyqngpm8d94k9r7-brltty-5.6/bin/brltty -v` and found version 5.6
- ran `/nix/store/4zz86z1wi6k5nny7wiyqngpm8d94k9r7-brltty-5.6/bin/brltty --version` and found version 5.6
- ran `/nix/store/4zz86z1wi6k5nny7wiyqngpm8d94k9r7-brltty-5.6/bin/brltty version` and found version 5.6
- ran `/nix/store/4zz86z1wi6k5nny7wiyqngpm8d94k9r7-brltty-5.6/bin/brltty -h` and found version 5.6
- ran `/nix/store/4zz86z1wi6k5nny7wiyqngpm8d94k9r7-brltty-5.6/bin/brltty --help` and found version 5.6
- ran `/nix/store/4zz86z1wi6k5nny7wiyqngpm8d94k9r7-brltty-5.6/bin/brltty help` and found version 5.6
- ran `/nix/store/4zz86z1wi6k5nny7wiyqngpm8d94k9r7-brltty-5.6/bin/brltty-trtxt -h` got 0 exit code
- ran `/nix/store/4zz86z1wi6k5nny7wiyqngpm8d94k9r7-brltty-5.6/bin/brltty-trtxt --help` got 0 exit code
- ran `/nix/store/4zz86z1wi6k5nny7wiyqngpm8d94k9r7-brltty-5.6/bin/brltty-ttb -h` got 0 exit code
- ran `/nix/store/4zz86z1wi6k5nny7wiyqngpm8d94k9r7-brltty-5.6/bin/brltty-ttb --help` got 0 exit code
- ran `/nix/store/4zz86z1wi6k5nny7wiyqngpm8d94k9r7-brltty-5.6/bin/brltty-atb -h` got 0 exit code
- ran `/nix/store/4zz86z1wi6k5nny7wiyqngpm8d94k9r7-brltty-5.6/bin/brltty-atb --help` got 0 exit code
- ran `/nix/store/4zz86z1wi6k5nny7wiyqngpm8d94k9r7-brltty-5.6/bin/brltty-ktb -h` got 0 exit code
- ran `/nix/store/4zz86z1wi6k5nny7wiyqngpm8d94k9r7-brltty-5.6/bin/brltty-ktb --help` got 0 exit code
- ran `/nix/store/4zz86z1wi6k5nny7wiyqngpm8d94k9r7-brltty-5.6/bin/brltty-tune -h` got 0 exit code
- ran `/nix/store/4zz86z1wi6k5nny7wiyqngpm8d94k9r7-brltty-5.6/bin/brltty-tune --help` got 0 exit code
- found 5.6 with grep in /nix/store/4zz86z1wi6k5nny7wiyqngpm8d94k9r7-brltty-5.6