ci: shorter job names

[phip1611]

Shorter + more descriptive CI job names.

I think the current names are too long for this view:

Checklist

• Sensible git history (for example, squash "typo" or "fix" commits). See the Rewriting History guide for help.
• Update the changelog (if necessary)

[phip1611]

Once merged, we need to update the branch protection settings in GitHub as the job names have changed.

[nicholasbishop]

Thanks, those longer names had been subtly bothering me as well :)