mlterm: 3.8.0 -> 3.8.4

Semi-automatic update. These checks were performed:

- built on NixOS
- ran `/nix/store/hl028yiknrqbkp4i12nn0nibr41rwgvn-mlterm-3.8.4/bin/mlterm help` got 0 exit code
- ran `/nix/store/hl028yiknrqbkp4i12nn0nibr41rwgvn-mlterm-3.8.4/bin/mlfc help` got 0 exit code
- ran `/nix/store/hl028yiknrqbkp4i12nn0nibr41rwgvn-mlterm-3.8.4/bin/mlcc -h` got 0 exit code
- ran `/nix/store/hl028yiknrqbkp4i12nn0nibr41rwgvn-mlterm-3.8.4/bin/mlcc --help` got 0 exit code
- ran `/nix/store/hl028yiknrqbkp4i12nn0nibr41rwgvn-mlterm-3.8.4/bin/mlclient -h` got 0 exit code
- ran `/nix/store/hl028yiknrqbkp4i12nn0nibr41rwgvn-mlterm-3.8.4/bin/mlclient --help` got 0 exit code
- ran `/nix/store/hl028yiknrqbkp4i12nn0nibr41rwgvn-mlterm-3.8.4/bin/mlclient help` got 0 exit code
- ran `/nix/store/hl028yiknrqbkp4i12nn0nibr41rwgvn-mlterm-3.8.4/bin/mlclientx -h` got 0 exit code
- ran `/nix/store/hl028yiknrqbkp4i12nn0nibr41rwgvn-mlterm-3.8.4/bin/mlclientx --help` got 0 exit code
- ran `/nix/store/hl028yiknrqbkp4i12nn0nibr41rwgvn-mlterm-3.8.4/bin/mlclientx help` got 0 exit code
- ran `/nix/store/hl028yiknrqbkp4i12nn0nibr41rwgvn-mlterm-3.8.4/bin/mlterm-fb help` got 0 exit code
- found 3.8.4 with grep in /nix/store/hl028yiknrqbkp4i12nn0nibr41rwgvn-mlterm-3.8.4
- found 3.8.4 in filename of file in /nix/store/hl028yiknrqbkp4i12nn0nibr41rwgvn-mlterm-3.8.4

cc "@vrthra @ramkromberg"