Fixes identified during v12 review:
Fixes identified during v12 review:

 * sentence about "duration" and "Episodes" was back to front.
 * s/2023/2021/
 * minor spelling and formatting issues.

For #2813

schemaorg/schemaorg,schemaorg/schemaorg,schemaorg/schemaorg,schemaorg/schemaorg,schemaorg/schemaorg