cht.sh: unstable-2018-11-02 -> unstable-2019-08-06

[evanjs]

Motivation for this change

Discovered cht.sh but then realized the CLI doesn't have shell completions in the version available on nixpkgs.
They're sort of helpful when you get past 1,000 options.

Closure size:

/nix/store/plz5ab1xlgp1gkv26y3skrbf27w5ka26-cht.sh-unstable-2018-11-02     45469952
/nix/store/vy2xm234qaizjy1iz4p4xc08sp4v3bn5-cht.sh-unstable-2019-08-06     45481360

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nix-review --run "nix-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.

Notify maintainers

cc @fgaz

[fgaz]

Thanks for helping maintain the package

[evanjs]

Thanks for helping maintain the package

Don't mention it!
Discovered this package via Reddit and noticed we didn't have tab completions and I knew I had to have it.

Better yet, it seems like @chubin is okay opening issues here after major updates, etc 🎉 (context)