### What do you see as an issue?

The documentation for zombie tasks https://airflow.apache.org/docs/apache-airflow/stable/core-concepts/tasks.html#zombie-undead-tasks is a bit abstract at the moment. There is a scope for enhancing the document by explaining how Airflow detects tasks as zombies

### Solving the problem

We can enhance the documentation by translating this query https://github.com/astronomer/airflow/blob/main/airflow/jobs/scheduler_job_runner.py#L1721 to a layman readable text in our documentation.

### Anything else

It might also help to add developer contribution steps to reproduce zombies locally.

### Are you willing to submit PR?

- [ ] Yes I am willing to submit a PR!

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)

"Not executing %s since the task concurrency per DAG run for"
                                " this task has been reached.",
                                task_instance,
                            )
                            starved_tasks_task_dagrun_concurrency.add(
                                (task_instance.dag_id, task_instance.run_id, task_instance.task_id)
                            )
                            continue
                executable_tis.append(task_instance)
                open_slots -= task_instance.pool_slots
                concurrency_map.dag_active_tasks_map[dag_id] += 1
                concurrency_map.task_concurrency_map[(task_instance.dag_id, task_instance.task_id)] += 1
                concurrency_map.task_dagrun_concurrency_map[
                    (task_instance.dag_id, task_instance.run_id, task_instance.task_id)
                ] += 1
                pool_stats["open"] = open_slots
            is_done = executable_tis or len(task_instances_to_examine) < max_tis
            
            found_new_filters = (
                len(starved_pools) > num_starved_pools
                or len(starved_dags) > num_starved_dags
                or len(starved_tasks) > num_starved_tasks
                or len(starved_tasks_task_dagrun_concurrency) > num_starved_tasks_task_dagrun_concurrency
            )
            if is_done or not found_new_filters:
                break
            self.log.info(
                "Found no task instances to queue on query iteration %s "
                "but there could be more candidate task instances to check.",
                loop_count,