Fix partial of hidden text on the side-bar which located in REST API Reference

[roharon]

Not shown partial of text(Endpoint path) located in the right side-bar which located in REST API Reference

Dose not changed to the next line

<a class="reference internal" href="#post--api-experimental-dags--DAG_ID--dag_runs">POST /api/experimental/dags/&lt;DAG_ID&gt;/dag_runs</a>

It seems to be problem caused by endpoint path that long. Also, hidden text amount is different each browser's zoom size

I think it must be shown like this image (that I modifed)