Add collection names to table that maps typecodes to class names

[eecavanna]

In PR #2319, a table was introduced to the schema documentation. The table had two columns:

• Typecode(s)
• Class name

The task here is to add a third column—Collection name—to the table. That column will contain the names of the MongoDB collection in which the schema allows instances of those classes to reside.

This feature was suggested by @aclum during the weekly metadata meeting on 1/15/2025.