[KeuqS]

Summary

• remove bash completion entries for the deprecated new-build, new-repl, new-run, new-test, new-bench, and new-haddock commands
• keep the existing new-install completion entry unchanged
• add a changelog entry for the user-visible completion change

Closes #12151

QA Notes

• Completion requests for the six deprecated new-* commands no longer enter the target-list completion path.
• new-install continues to use executable target completion.

Validation

• git diff --check
• verified the deprecated completion entries are absent and new-install remains present
• shellcheck and the Bash 3 compatibility check could not be run locally because Bash/ShellCheck are not installed on the Windows host

Checklist

• The change is recorded in changelog.d/12151.md.
• QA notes are included above.
• Automated tests have not been added; this repository has no test harness for this completion script.

[Mikolaj]

Why not remove this one?

[Bodigrim]

Please apply "AI-assisted" label. Please use a relevant PR template.

• shellcheck and the Bash 3 compatibility check could not be run locally because Bash/ShellCheck are not installed on the Windows host

Honestly, I don't find proxying unfiltered AI responses helpful.

[ulysses4ever]

I agree that there PR template should have been preserved and that the description should have been proofread before posting. At the same time I recognize that it is a low-cost minor cleanup that I don’t want to hold on those grounds.