doc/languages-frameworks/rust: example for disabling tests

[0x4A6F]

Description of changes

Add an example for disabling test for rust.

There are two prevalent invocations in checkFlags:

• "--skip=testname"
rg -l 'buildRustPackage' pkgs | xargs rg -l 'skip=' | wc -l -> 43
• "--skip testname"
rg -l 'buildRustPackage' pkgs | xargs rg -l 'skip ' | wc -l -> 24
• "--skip" "testname"
rg -l 'buildRustPackage' pkgs | xargs rg -l 'skip" ' | wc -l -> 1

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandbox = true set in nix.conf? (See Nix manual)
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 22.11 Release Notes (or backporting 22.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
  • (Release notes changes) Ran nixos/doc/manual/md-to-db.sh to update generated release notes
• Fits CONTRIBUTING.md.

[flokli]

Is there any upstream documentation on the --skip argument? I'd probably go with the style that's used there, not what's mostly used in nixpkgs.

[figsoda]

"--skip testname" is wrong, it's either "--skip=testname" or "--skip" "testname"