mappings/Veg+-VegCore.csv: previousCatalogNumber: Removed no longer needed "According to" comment, because this is now documented in the mappings/Veg+.terms.csv entry. Note that the citation for any mapping is the overlap of the terms' definitions, and thus only the definitions need to be cited, not the mapping itself. (The definitions are provided in the links in mappings/Veg+.terms.csv.)