Treat a job as suspended when any child process suspends

[magicant]

POSIX.1-2024 requires that the shell treat a job as suspended when any child process comprising the job suspends. Previously, the shell considered a job to be suspended only when all child processes comprising the job suspended. This change makes the shell compliant with the standard.

Fixes #130

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This pull request includes various changes related to job control behavior in the shell, documentation updates, and test adjustments. The most important changes include modifications to how the shell handles suspended jobs, updates to documentation in multiple languages, and the addition of new test cases.

Changes to job control behavior:

• Modified the shell to consider a job as suspended when any child process in a pipeline suspends, instead of waiting for all child processes to suspend (job.c).

Documentation updates:

• Updated the NEWS file to reflect the change in job suspension behavior.
• Updated the Japanese NEWS.ja file with the corresponding change.
• Revised the English and Japanese job control documentation to align with the new behavior (doc/job.txt, doc/ja/job.txt). [1] [2]

Test adjustments:

• Added new test cases to ensure the shell considers a job suspended when any child process suspends (tests/job-y.tst).
• Reorganized the test suite to include job control tests under a new section in tests/POSIX.