Remove trailing period from errmsg in subscriptioncmds.c.

Author: Sahitya Chandra <sahityajb@gmail.com>
Discussion: https://postgr.es/m/20260308142806.181309-1-sahityajb@gmail.com

src/backend/commands/subscriptioncmds.c

@@ -2993,7 +2993,7 @@ check_pub_dead_tuple_retention(WalReceiverConn *wrconn)
 	if (remote_in_recovery)
 		ereport(ERROR,
 				errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				errmsg("cannot enable retain_dead_tuples if the publisher is in recovery."));
+				errmsg("cannot enable retain_dead_tuples if the publisher is in recovery"));
 
 	ExecDropSingleTupleTableSlot(slot);