Some small tidying up of the docs site

Signed-off-by: Peter Macdonald <peterm4c@pm.me>

docs/plugins/existing-plugins.md

@@ -1,18 +0,0 @@
----
-id: existing-plugins
-title: Existing plugins
-description: Lists of existing open source plugins
----
-
-## The Plugin Directory
-
-Open source plugins that you can add to your Backstage deployment can be found
-at:
-
-https://backstage.io/plugins
-
-![](https://backstage.io/blog/assets/marketplace.png)
-
-## Links
-
-- [[blog] The Plugin Directory is open](https://backstage.io/blog/2020/09/30/plugin-marketplace)

docs/plugins/index.md

@@ -23,3 +23,9 @@ This approach is equally beneficial if you conceive an idea for a potentially im
 ## Integration with the Software Catalog
 
 Should your plugin complement the Software Catalog rather than exist as a standalone feature (for instance, as an additional tab or a card within an "Overview" tab), you'll find comprehensive guidance on achieving this integration in the [Integrating Plugin into Software Catalog guide](integrating-plugin-into-software-catalog.md).
+
+## Existing Plugins
+
+There are a plethora of existing community made plugins which can be found by going to the [Backstage Plugin Directory](https://backstage.io/plugins)
+
+You can read more about it in this blog post: [The Plugin Directory is now open](https://backstage.io/blog/2020/09/30/plugin-marketplace/)

docs/plugins/testing.md

@@ -4,6 +4,12 @@ title: Testing with Jest
 description: Documentation on How to do unit testing with Jest
 ---
 
+:::note Note
+
+You may want to consider migrating to Jest 30, to do this, you can follow this guide: [Migrating to Jest 30](../tutorials/jest30-migration.md)
+
+:::
+
 Backstage uses [Jest](https://facebook.github.io/jest/) for all our unit testing
 needs.
 
@@ -185,6 +191,11 @@ loading is broken, not that the loading indicator is broken.
 
 ## Examples
 
+For more specific examples of how to test your Backstage **backend plugins** and **modules** or **frontend plugins** you can check out the following guides:
+
+- [Testing Backend Plugins and Modules](../backend-system/building-plugins-and-modules/02-testing.md)
+- [Testing Frontend Plugins](../frontend-system/building-plugins/02-testing.md)
+
 ### Utility Functions
 
 A utility function is a function with no side effects. It takes in arguments and