Taxon data is stored as a set of taxa with taxon ids and parent taxon
ids. For any given dataset, the set should include all parent taxa
required. This internal function takes such list of taxon data and
adds columns showing the taxonomic hierarchy for each row. It is used by
get_taxa and get_taxon_coverage.
taxon_index_to_taxon_table(taxa)An existing object of class safedata
A data frame adding higher taxon level information for each taxon