Clarify that some fields are recent presentation.
Clarify that some fields are recent presentation.

Some of the fields in solr we populate with the most recent presentation, make it clear that this is what we're doing.
ox-it/wl-course-signup,ox-it/wl-course-signup,ox-it/wl-course-signup,ox-it/wl-course-signup,ox-it/wl-course-signup