**Apache Airflow version**:

master

**Kubernetes version (if you are using kubernetes)** (use `kubectl version`):

**Environment**: breeze

**What happened**:

This DAG
```python
from airflow import models
from airflow.operators.dummy_operator import DummyOperator
from airflow.utils.dates import days_ago

with models.DAG("test", start_date=days_ago(1), schedule_interval=None,) as dag:
    t1 = DummyOperator(task_id="t1")
    t2 = DummyOperator(task_id="t2")
    t1 >> t2
```

is rendering like that:

<img width="1374" alt="Screenshot 2020-08-27 at 19 59 41" src="https://user-images.githubusercontent.com/9528307/91478403-11d7fb00-e8a0-11ea-91d0-d7d578bcb5a2.png">

**What you expected to happen**:

I expect to see same relations as defined in DAG file

**How to reproduce it**:

Render the example DAG from above.


**Anything else we need to know**:

I'm surprised by this bug 👀 

airflow/www/views.py
else:
            config = (
                "# Your Airflow administrator chose not to expose the "
                "configuration, most likely for security reasons.")
            table = None
        if raw:
            return Response(
                response=config,
                status=200,
                mimetype="application/text")
        else:
            code_html = Markup(highlight(
                config,
                lexers.IniLexer(),  
                HtmlFormatter(noclasses=True))
            )
            return self.render_template(
                'airflow/config.html',
                pre_subtitle=settings.HEADER + "  v" + airflow.__version__,
                code_html=code_html, title=title, subtitle=subtitle,
                table=table)
class RedocView(AirflowBaseView):
    """Redoc Open API documentation"""
    default_view = 'redoc'
    @expose('/redoc')
    def redoc(self):
        """Redoc API documentation."""
        openapi_spec_url = url_for("/api/v1./api/v1_openapi_yaml")
        return self.render_template('airflow/redoc.html', openapi_spec_url=openapi_spec_url)
class DagFilter(BaseFilter):