Clarify 8.1.3 acceptedOffer properties

[nickevansuk]

Currently 8.1.3 reads:

With the exception of openBookingFlowRequirement, the Offer properties present in the Opportunity Data [RPDE] open feeds must exactly match those in the acceptedOffer consistently in responses to C1, C2, P, and B. acceptedOffer must also include the same properties in the Orders feed, unless the Booking System does not support Replacement.

To aid clarity for the reader, perhaps it should instead read:

With the exception of openBookingFlowRequirement, the same Offer properties and values must be present in both the Opportunity Data [RPDE] open feeds and in the acceptedOffer object returned in responses to C1, C2, P, and B. acceptedOffer must also include the same properties in the Orders feed, unless the Booking System does not support Replacement, in which case acceptedOffer may be omitted from the Orders feed.