### Body

There are some use cases where users want to trigger new DAG run as soon as one finished. This is a request I've seen several times with some variations (for example like this [Stackoverflow question](https://stackoverflow.com/q/75623153/14624409)) but the basic request is the same.

The workaround users do to get such functionality is place `TriggerDagRunOperator` as last task of their DAG invoking the same DAG:

```
from datetime import datetime

from airflow import DAG
from airflow.operators.empty import EmptyOperator
from airflow.operators.trigger_dagrun import TriggerDagRunOperator

with DAG(
    dag_id="example",
    start_date=datetime(2023, 1, 1,),
    catchup=False,
    schedule=None,
) as dag:
    task = EmptyOperator(task_id="first")
    trigger = TriggerDagRunOperator(
        task_id="trigger",
        trigger_dag_id="example",
    )

    task >> trigger

```

As you can see this works nicely:
![Screenshot 2023-03-03 at 14 20 51](https://user-images.githubusercontent.com/45845474/222718862-dfde8a41-24b6-4991-b318-b7f9784514f6.png)

My suggestion is to add first class support for this use case, so the above example will be changed to:

```

from datetime import datetime

from airflow import DAG
from airflow.operators.empty import EmptyOperator
from airflow.operators.trigger_dagrun import TriggerDagRunOperator

with DAG(
    dag_id="example",
    start_date=datetime(2023, 1, 1,),
    catchup=False,
    schedule="@continues",
) as dag:
    task = EmptyOperator(task_id="first")
```

I guess it won't exactly be `"@continues"` but more likely new [ScheduleArg](https://github.com/apache/airflow/blob/8b8552f5c4111fe0732067d7af06aa5285498a79/airflow/models/dag.py#L127) type but I show it like that just for simplification of the idea.

### Committer

- [X] I acknowledge that I am a maintainer/committer of the Apache Airflow project.
...
        dag = noop_pipeline()
        assert isinstance(dag, DAG)
        assert dag.dag_id == "test"
    def test_default_dag_id(self):
        """Test that @dag uses function name as default dag id."""
        @dag_decorator(default_args=self.DEFAULT_ARGS)
        def noop_pipeline():
            ...
        dag = noop_pipeline()
        assert isinstance(dag, DAG)
        assert dag.dag_id == "noop_pipeline"
    @pytest.mark.parametrize(
        argnames=["dag_doc_md", "expected_doc_md"],
        argvalues=[
            pytest.param("dag docs.", "dag docs.", id="use_dag_doc_md"),
            pytest.param(None, "Regular DAG documentation", id="use_dag_docstring"),
        ],
    )
    def test_documentation_added(self, dag_doc_md, expected_doc_md):
        """Test that @dag uses function docs as doc_md for DAG object if doc_md is not explicitly set."""
        @dag_decorator(default_args=self.DEFAULT_ARGS, doc_md=dag_doc_md)
        def noop_pipeline():
            """Regular DAG documentation"""
        dag = noop_pipeline()
        assert isinstance(dag, DAG)
        assert dag.dag_id == "noop_pipeline"
        assert dag.doc_md == expected_doc_md
    def test_documentation_template_rendered(self):