Update docs/book/src/SUMMARY.md

Co-authored-by: Erik Mogensen <[email protected]>

Author: camilamacedo86

docs/book/src/SUMMARY.md

@@ -77,7 +77,7 @@
   - [Raising Events](./reference/raising-events.md)
   - [Watching Resources](./reference/watching-resources.md)
     - [Owned Resources](./reference/watching-resources/secondary-owned-resources.md)
-    - [Not Owned Resources](./reference/watching-resources/secondary-resources-not-owned)
+    - [Not Owned Resources](./reference/watching-resources/secondary-resources-not-owned.md)
     - [Using Predicates](./reference/watching-resources/predicates-with-watch.md)
   - [Kind for Dev & CI](reference/kind.md)
   - [What's a webhook?](reference/webhook-overview.md)