[chrikrah]

This extends hidden=True ("Hide this command from help outputs") to typer <app> utils docs. --help skips them, but the generated Markdown still lists hidden commands and sub-apps. Refs #1750, which the stale bot closed in June after its coverage check failed. Hidden options were already skipped.

$ typer tests.assets.cli.hidden_app utils docs --name hiddenapp
# master a5882de: lists `secret` and `internal`, plus sections for both and `internal rebuild`
# this branch:    only `public`
$ pytest tests/test_cli/test_doc.py -q
# a5882de with the new test: 1 failed (test_doc_hidden_commands), 8 passed
# this branch:               9 passed
$ TERMINAL_WIDTH=3000 _TYPER_FORCE_DISABLE_TERMINAL=1 pytest -q -n 4 [--cov on the branch]    # Python 3.12, Linux
# a5882de: 1473 passed, 30 skipped, 2 xfailed. this branch: 1474 passed, typer/cli.py at 100%
$ bash scripts/lint.sh    # mypy 2.4.1, ty 0.0.84, ruff 0.17.3
# clean

Docs that published a hidden command on purpose lose it, and I left an opt-in flag out until someone needs one. Should it land here instead?