docs: clarified where ordering_key will be written if write_metadata is set

PiperOrigin-RevId: 551210991

Source-Link: googleapis/googleapis@7c762d7

Source-Link: googleapis/googleapis-gen@15fe4c5
Copy-Tag: eyJwIjoiYXBpcy9Hb29nbGUuQ2xvdWQuUHViU3ViLlYxLy5Pd2xCb3QueWFtbCIsImgiOiIxNWZlNGM1ZmY1ZWJkNTI5MTFiNDI5YjA1Yjk5MmUyMzJmNTMzNTFlIn0=

Author: gcf-owl-bot[bot]

apis/Google.Cloud.PubSub.V1/Google.Cloud.PubSub.V1/Pubsub.g.cs

@@ -8715,7 +8715,11 @@ public AvroConfig Clone() {
         private bool writeMetadata_;
         /// <summary>
         /// When true, write the subscription name, message_id, publish_time,
-        /// attributes, and ordering_key as additional fields in the output.
+        /// attributes, and ordering_key as additional fields in the output. The
+        /// subscription name, message_id, and publish_time fields are put in their
+        /// own fields while all other message properties other than data (for
+        /// example, an ordering_key, if present) are added as entries in the
+        /// attributes map.
         /// </summary>
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
         [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]