Merge topic 'preset-test-jobs'

23615b7ca4 presets: Allow jobs to match `ctest -j` with no value
71ff5a9d6f presets: Disallow negative values for "jobs" fields
c2b773cb97 cmake: Prefer named constant for jobs
68bd63c856 Help/presets: Document behavior for unbounded parallelism
25641fe8d5 Help/presets: Document behavior for native build tool parallelism

Acked-by: Kitware Robot <kwrobot@kitware.com>
Acked-by: Alex Overchenko <aleksandr9809@gmail.com>
Merge-request: !11508