DOCS-5672 clarify --drop for mongorestore

Author: kay-kim

source/includes/options-mongorestore.yaml

@@ -236,16 +236,19 @@ name: drop
 directive: option
 args: null
 description: |
-  Modifies the restoration procedure to drop every collection from the
-  target database before restoring the collection from the dumped backup.
+  Before restoring the collections from the dumped backup, drops the
+  collections from the target database. {{role}} does not drop
+  collections that are not in the backup.
+
+  When the restore includes the ``admin`` database, {{program}} with
+  {{role}} removes all user credentials and replaces them with the
+  users defined in the dump file. Therefore, in systems with
+  :setting:`~security.authorization` enabled, {{program}} must be able
+  to authenticate to an existing user *and* to a user defined in the
+  dump file. If {{program}} can't authenticate to a user defined in the
+  dump file, the restoration process will fail, leaving an empty
+  database.
 
-  With {{role}} specified, {{program}} removes all user
-  credentials and replaces them with users defined in the dump
-  file. Therefore, in systems with :setting:`~security.authorization`
-  enabled, {{program}} must be able to authenticate to an existing
-  user *and* to a user defined in the dump file. If {{program}} can't
-  authenticate to a user defined in the dump file, the restoration
-  process will fail, leaving an empty database.
 optional: true
 ---
 program: mongorestore