Document handling of "subject"

[pdurbin]

Looking into #1430 revealed that behavior with regard to dcterms:subject in SWORD has changed from 3.6 to 4.0. In 3.6 this field mapped to keyword. Now it maps to both keyword and subject with special processing if the value matches the controlled vocabulary. This should be documented.

[posixeleni]

@pdurbin I had documented this new mappin behavior in the DC Terms - Dataverse DB Element Crosswalk in the SWORD API documentation see #1077 but for some reason this table is no longer showing in the guide. Who removed this?

[posixeleni]

@pdurbin - I fixed the display issue someone had improperly edited the table markdown causing it to not be recognized by Sphinx or GitHub https://github.com/IQSS/dataverse/blob/master/doc/sphinx-guides/source/api/sword.rst

The documentation for how we handle dcterms:subject is in the crosswalk table and can be sent to QA

[eaquigley]

@posixeleni thanks for making this change. closing ticket as this is now found in the crosswalk table.

[pdurbin]

Actually, more importantly (I believe), the example XML shows how you can use controlled vocabulary values in dcterms:subject now:

   <!-- Dataverse controlled vocabulary subject term -->
   <dcterms:subject>Chemistry</dcterms:subject>
   <!-- keywords -->
   <dcterms:subject>coffee</dcterms:subject>

[posixeleni]

@pdurbin both help 👍