docs: rename index

Author: xchopin

docs/administrator/mongo_indices.md

@@ -46,15 +46,15 @@ The concept of an index in MongoDB is the same as in relational databases. An in
 |:-----------:|:----------------------------------:|
 |     user    | userSourcedId, orgId, tenantId     |
 |  line_item  | lineitemSourcedId, orgId, tenantId |
-| primary_key | result.sourcedId, orgId, tenantId  |
+|composite_key| result.sourcedId, orgId, tenantId  |
 | most_recent |    result.date, orgId, tenantId    |
 
 <br>
 
 ### MongoUser
 |    Index    |               Keys               |
 |:-----------:|:--------------------------------:|
-| primary_key | user.sourcedId, orgId, tenantId  |
+|composite_key| user.sourcedId, orgId, tenantId  |
 
 
 <br>