Blurb: validate GitHub issue number #504
Description
The short story
It would be nice if we checked GitHub issue numbers are valid.
Long version
Thanks for blurb!
If you accidentally use an (old) GitHub PR number instead of the GitHub issue number, the CI docs build will fail:
Building NEWS from Misc/NEWS.d with blurb
PATH=./venv/bin:$PATH sphinx-build -b html -d build/doctrees -j auto -q -W --keep-going . build/html
Error: ../build/NEWS:7[15](https://github.com/python/cpython/actions/runs/5021764661/jobs/9004477237#step:7:16): ERROR: The GitHub ID '13[17](https://github.com/python/cpython/actions/runs/5021764661/jobs/9004477237#step:7:18)2' seems too low -- use :issue:`...` for BPO IDs
make: *** [Makefile:50: build] Error 1
Re:
- https://github.com/python/cpython/actions/runs/5021764661/jobs/9004477237
- gh-81005: Refactor str tests to reflect that str and unicode are merged in Python 3 cpython#13172 (comment)
This is validated in https://github.com/python/cpython/blob/616fcad6e2e10b0d0252e7f3688e61c468c54e6e/Doc/tools/extensions/pyspecific.py#L69-L79
Shall we add some validation to Blurb, to fail sooner?
We could also allow old BPO issue numbers similar to https://github.com/python/cpython/blob/616fcad6e2e10b0d0252e7f3688e61c468c54e6e/Doc/tools/extensions/pyspecific.py#L54-L63, but for new NEWS files created today, should we require only the corresponding GitHub issue number?