lints workflow : feature or crate selection

Documenting an issue encountered in https://github.com/lurk-lab/neptune/pull/255, which is arguably the fault of the crate organization:
- the gbench crate (which is non-publish!) runs with the default opencl feature, which does not compile on some CI machines:
https://github.com/lurk-lab/neptune/blob/main/gbench/Cargo.toml#L25
- the lint crate runs with `workspace` in the doc step of the job:
https://github.com/lurk-lab/neptune/actions/runs/7294189991/job/19878612122?pr=255
https://github.com/lurk-lab/ci-workflows/blob/96e567fa741858807c1de28bb4d8194291faecfb/.github/workflows/lints.yml#L49

Three ways to solve this:
- make the gbench feature non-default, just generate a runtime panic if neither of opencl nor cuda are active,
- allow excluding a crate from the doc test,
- allow excluding a feature (or running with default-deatures = false) from the doc test,

Empieza leyendo .github/workflows/lints.yml en ci-workflows, la definición de features de gbench/Cargo.toml y el PR #255 mencionado. Compara cómo el paso de documentación invoca el crate de lint y determina qué crate o comportamiento de selección de features debería admitirse. Se considera terminado cuando el workflow puede gestionar los casos documentados de crate y selección de features sin fallar por features predeterminadas no compatibles.

Escrito por el modelo de indexación a partir del texto del issue.