Documentation: Document taskset command.

[Zepp-Hanzj]

Summary

• Fill the blank Documentation/applications/system/taskset/index.rst command reference page.
• Document the source-backed command forms: taskset <mask> <command> [args ...], taskset -p [mask] <pid>, and taskset -h.
• Document the CONFIG_SYSTEM_TASKSET enable option, its CONFIG_SMP && CONFIG_SYSTEM_SYSTEM dependency, and the related program name / priority / stack-size options.
• Keep the patch documentation-only and scoped to one .rst file.
• Refs Documentation: blank pages in documentation #11081.

Impact

• Is new feature added? NO.
• Is existing feature changed? NO.
• Impact on user (will user need to adapt to change)? NO; this only adds missing documentation for an existing command.
• Impact on build (will build process change)? NO.
• Impact on hardware (will arch(s) / board(s) / driver(s) change)? NO.
• Impact on documentation (is update required / provided)? YES; the previously blank taskset command page is filled.
• Impact on security (any sort of implications)? NO.
• Impact on compatibility (backward/forward/interoperability)? NO.
• Anything else to consider or add? Documentation claims were checked against apps/system/taskset/taskset.c and apps/system/taskset/Kconfig from nuttx-apps upstream master.

Testing

I confirm that changes are verified on local setup and work as intended:

• Build Host(s): WSL2 Linux x86_64 (Linux DESKTOP-6B1686O 6.6.114.1-microsoft-standard-WSL2), Python 3.8.10, Sphinx 7.1.2, PlantUML available on PATH.
• Target(s): documentation-only change; no hardware target needed.
• Source verification:
  • git -C /home/hanzj/workspace/nuttxspace/apps show upstream/master:system/taskset/taskset.c
  • git -C /home/hanzj/workspace/nuttxspace/apps show upstream/master:system/taskset/Kconfig

Testing logs before change:

Documentation/applications/system/taskset/index.rst contained only the page title.
Duplicate check found no open PR specifically documenting taskset.

Testing logs after change:

$ cd Documentation
$ DISPLAY= JAVA_TOOL_OPTIONS='-Djava.awt.headless=true' make html
Running Sphinx v7.1.2
...
build succeeded.

The HTML pages are in _build/html.

PR verification Self-Check

• This PR introduces only one functional change.
• I have updated all required description fields above.
• My PR adheres to Contributing Guidelines and Documentation (git commit title and message, coding standard, etc).
• My PR is still work in progress (not ready for review).
• My PR is ready for review and can be safely merged into a codebase.

[linguini1]

BTW, I don't think your using the right process to build docs locally. You should follow: https://nuttx.apache.org/docs/latest/contributing/documentation.html#building

[Zepp-Hanzj]

Thanks for pointing that out. I re-ran the documentation validation using the documented build entrypoint (cd Documentation && make html) instead of the earlier direct Sphinx dummy-builder command, and updated the PR Testing section accordingly.

One local WSL note: plantuml initially tried to use the inherited X11 DISPLAY, so I reran the same make html build with DISPLAY= and JAVA_TOOL_OPTIONS='-Djava.awt.headless=true'; that completed successfully with build succeeded and generated _build/html.

[linguini1]

Thanks for pointing that out. I re-ran the documentation validation using the documented build entrypoint (cd Documentation && make html) instead of the earlier direct Sphinx dummy-builder command, and updated the PR Testing section accordingly.

No worries, the CI passed fine. Just letting you know in case it would cause issues for you at some point.

One local WSL note: plantuml initially tried to use the inherited X11 DISPLAY, so I reran the same make html build with DISPLAY= and JAVA_TOOL_OPTIONS='-Djava.awt.headless=true'; that completed successfully with build succeeded and generated _build/html.

Good to know, maybe worth adding that to the docs :)