Give the new version number (9) also in description field(s?)

[awagner-mainz]

See

tei-publisher-app/modules/lib/api.json

Line 6 in 2ef1cc0

"description": "This is the core API for TEI Publisher 8. It describes all endpoints used by TEI Publisher web components, plus additional operations added for external access."

, where it still says "This is the core API for TEI Publisher 8".