Suggest to search all issues, not just open

Author: mathbunnyru

docs/contributing/issues.md

@@ -7,7 +7,7 @@ Please review the following guidelines when reporting your problem.
   please report it to [[email protected]](mailto:[email protected]), **not in the issue trackers on GitHub**.
   If you prefer to encrypt your security reports, you can use [this PGP public key](https://github.com/jupyter/jupyter.github.io/blob/HEAD/assets/ipython_security.asc).
 - If you think your problem is unique to the Jupyter Docker Stacks images,
-  please search the [jupyter/docker-stacks issue tracker](https://github.com/jupyter/docker-stacks/issues)
+  please search the [jupyter/docker-stacks issue tracker](https://github.com/jupyter/docker-stacks/issues?q=is%3Aissue%20)
   to see if someone else has already reported the same problem.
   If not, please open a [GitHub bug report issue](https://github.com/jupyter/docker-stacks/issues/new?template=bug_report.yml)
   and provide all the information requested in the issue template.