only check for issue number, to accomodate `misc` category

[zacharyburnett]

Description

Checklist:

• [ ] pre-commit checks ran successfully
• [ ] tests ran successfully
• [ ] for a public change, added news fragment (changes/<PR#>.<changetype>.rst)
• [ ] for a public change, updated documentation
• [ ] for any new features, unit tests were added

[braingram]

:sad trombone: RTD is still unhappy:

The ASDF Standard is at v1.6.0
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
../CHANGES.rst:127: CRITICAL: Title level inconsistent: