Fix typos

[wxtim]

Follow-up to #136

Checklist

• I have read the contributing instructions in README.md and have opened this against the correct branch & milestone

[MetRonnie]

@wxtim It seems we've still got some issues with the new format: https://github.com/cylc/release-actions/actions/runs/21570770992/job/62149466610?pr=142

pip install git+https://github.com/cylc/cylc-flow@8.4.0#egg=cylc-flow[all]
error: invalid-egg-fragment

× The 'cylc-flow[all]' egg fragment is invalid
╰─> from 'git+https://github.com/cylc/cylc-flow@8.4.0#egg=cylc-flow[all]'

hint: Try using the Direct URL requirement syntax: 'name[extra] @ URL'