docs: Add clarification for TaskGroup.parallelism

PiperOrigin-RevId: 577945369

Source-Link: googleapis/googleapis@5a7e895

Source-Link: https://github.com/googleapis/googleapis-gen/commit/b9705e9e82696baf2b37e68990b71d83fe08dbf6
Copy-Tag: eyJwIjoiYXBpcy9Hb29nbGUuQ2xvdWQuQmF0Y2guVjFBbHBoYS8uT3dsQm90LnlhbWwiLCJoIjoiYjk3MDVlOWU4MjY5NmJhZjJiMzdlNjg5OTBiNzFkODNmZTA4ZGJmNiJ9

apis/Google.Cloud.Batch.V1Alpha/Google.Cloud.Batch.V1Alpha/Job.g.cs

@@ -6725,7 +6725,8 @@ public sealed partial class TaskGroup : pb::IMessage<TaskGroup>
     private long parallelism_;
     /// <summary>
     /// Max number of tasks that can run in parallel.
-    /// Default to min(task_count, 1000).
+    /// Default to min(task_count, parallel tasks per job limit).
+    /// See: [Job Limits](https://cloud.google.com/batch/quotas#job_limits).
     /// Field parallelism must be 1 if the scheduling_policy is IN_ORDER.
     /// </summary>
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute]