feat(flake-module)!: a flake check for each devshell

[mightyiam]

Here is a nix flake show

git+file:///home/mightyiam/s/numtide/devshell?dir=templates/flake-parts ├───checks │ ├───aarch64-darwin │ │ └───"devshells/default" omitted (use '--all-systems' to show) │ ├───aarch64-linux │ │ └───"devshells/default" omitted (use '--all-systems' to show) │ ├───i686-linux │ │ └───"devshells/default" omitted (use '--all-systems' to show) │ ├───x86_64-darwin │ │ └───"devshells/default" omitted (use '--all-systems' to show) │ └───x86_64-linux │ └───"devshells/default": derivation 'devshell' └───devShells ├───aarch64-darwin │ └───default omitted (use '--all-systems' to show) ├───aarch64-linux │ └───default omitted (use '--all-systems' to show) ├───i686-linux │ └───default omitted (use '--all-systems' to show) ├───x86_64-darwin │ └───default omitted (use '--all-systems' to show) └───x86_64-linux └───default: development environment 'devshell' 

And here are some questions:

• Should this be on by default?
  I think it should, but that would add flake outputs to existing users when they bump this input.
  Not sure that's acceptable in this community.
• Would adding this require also adding an option to enable this?
• This should also be documented when other questions are answered.
• Tests? Not sure I see any existing flake-module tests...

[mightyiam]

hercules-ci/flake-parts#275