Issue coverage for version 9.0

• LearningResource Add a "LearningResource" type that can indicate learning-oriented educational content (and events, products...) #1401 and Quiz Create Quiz type #2611
• ProductGroup / isVariantOf Change the domain and range of isVariantOf to Product #1797, ProductCollection Add subtype of /Collection for collections of products (/ProductCollection) #2605 (and /includesObject), variant properties (size, pattern) for products Improve expressivity for some specific common product variant attributes (size, pattern) #2587.
• Site fixes and model tidying around Enumerations Reformat status type enumeration lists to be nested under StatusEnumeration #2604 (PR issue-2604 reformat status type enumeration #2609).
• Improved examples coverage Various examples added #2620
• Add byMonthWeek to Schedule Add byMonthWeek as a property of schema.org/Schedule #2599
• Add BoatTrip, BoatReservation, BoatTerminal Proposal: BoatTrip, BoatStop, Harbor #1755