Add detail to description of finding reviewers

[joelnitta]

The Tips for reviewer search in Airtable section shows a screenshot of filtering the data based on reviewer expertise, but does not indicate the table to use for filtering. There are many possible tables (e.g., reviewers-prod, reviews, packages, authors, reviewers, etc.) so it would be good to clarify this.

[maelle]

@mpadge do we mean a table here, or the nice interface that I think Noam had created?

[mpadge]

@maelle I asked Joel in #1010, because the link should just go to the nice interface, but from out chat it seemed he was maybe seeing the full table?