Merge pull request #35230 from Iceber/fix_retainKeys_example

the retainKeys strategy only works in the strategic merge patch

Author: k8s-ci-robot

content/en/docs/tasks/manage-kubernetes-objects/update-api-object-kubectl-patch.md

@@ -309,7 +309,7 @@ spec:
 Patch your Deployment:
 
 ```shell
-kubectl patch deployment retainkeys-demo --type merge --patch-file patch-file-no-retainkeys.yaml
+kubectl patch deployment retainkeys-demo --type strategic --patch-file patch-file-no-retainkeys.yaml
 ```
 
 In the output, you can see that it is not possible to set `type` as `Recreate` when a value is defined for `spec.strategy.rollingUpdate`: