Provide more details on the difference between "SIMPLE_CSV" and "DWCA" format in help documentation

[user3386170]

I was recently helped by a user on StackOverflow to resolve how to get more fields (attributes) from my occ_download. He pointed out that using DWCA instead of SIMPLE_CSV allows for more complete downloads. The help documentation is currently rather sparse on the subject (https://www.rdocumentation.org/packages/rgbif/versions/3.8.0/topics/occ_download).

format (character) The download format. One of 'DWCA' (default), 'SIMPLE_CSV', or 'SPECIES_LIST'

It would helpful to mention at the very least "DWCA provides a more complete set of fields stored in multiple files while SIMPLE_CSV provides a succinct output in a single file that restricts the fields available for download". And, if possible, provide a full list of which fields are available for download in each format. Alternatively, filling out this page on the gbif website could help with a link towards it. https://techdocs.gbif.org/en/openapi/v1/occurrence#/Occurrence%20download%20formats/describeDwcaDownload

[jhnwllr]

@user3386170 Thank you for the feedback, I will include this in the next release.