dcrochu as of 26/02/2025 plus rsigns and the following changes: removed "Domino", adapting the melody according to the franciscan mss; changed Offerentur to Afferentur, following BR, because we cannot justify not following BR, as the change is trivial; changed the beginning of the altera pars and the punctuation to reflect the structure found in BR.

TODO make sure that both Afferentur and Offerentur are indexed in the book.