collection singular

Signed-off-by: Josh Horton <joshh@us.ibm.com>

docs/source/gateway.md

@@ -62,7 +62,7 @@ stored on the endorsement peer's ledger).
 
 The gateway is dependent on the [discovery service](discovery-overview.html) to get the connection details of both the available peers and ordering service nodes, and for calculating the combination of peers that are required to endorse the transaction proposal. The discovery service must therefore always remain enabled on the Fabric Gateway peer.
 
-The gateway endorsement process is more restrictive for transient data because it often contains sensitive or personal information that must not persist in the ledger. In this case, the gateway will restrict the set of endorsing organizations to those that are members of the private data collections to be accessed (either read or write). If this restriction for transient data results in failed endorsement, the gateway rejects the transaction proposal. If rejected, the client should [explicitly define which organizations should endorse](#how-to-override-endorsement-policy-detection) the transaction, which must be restricted to members of the private data collection.
+The gateway endorsement process is more restrictive for transient data because it often contains sensitive or personal information that must not persist in the ledger. In this case, the gateway will restrict the set of endorsing organizations to those that are members of the private data collection to be accessed (either read or write). If this restriction for transient data results in failed endorsement, the gateway rejects the transaction proposal. If rejected, the client should [explicitly define which organizations should endorse](#how-to-override-endorsement-policy-detection) the transaction, which must be restricted to members of the private data collection.
 
 ### Targeting specific endorsement peers