Links broken in `Templates` doc

### What do you see as an issue? https://airflow.apache.org/docs/apache-airflow/stable/templates-ref.html The links for objects such as `DagRun` / `DAG` / `TaskInstance` / `BaseOperator` appear no longer functional - which makes it quite difficult to tell what you can actually get from those objects while accessing them via jinja templates (or via `Context`) ### 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)