Added instructions for enabling Istio CNI on k3s (#480)

* Added instructions for enabling Istio CNI on k3s

* Use tabs for rke2 + k3s

* Implement spellcheck feedback

docs/integrations-in-rancher/istio/configuration-options/install-istio-on-rke2-cluster.md

@@ -1,5 +1,5 @@
 ---
-title: Additional Steps for Installing Istio on an RKE2 Cluster
+title: Additional Steps for Installing Istio on RKE2 and K3s Clusters
 ---
 
 When installing or upgrading the Istio Helm chart through **Apps,**
@@ -8,30 +8,53 @@ When installing or upgrading the Istio Helm chart through **Apps,**
 1. You will see options for configuring the Istio Helm chart. On the **Components** tab, check the box next to **Enabled CNI**.
 1. Add a custom overlay file specifying `cniBinDir` and `cniConfDir`. For more information on these options, refer to the [Istio documentation.](https://istio.io/latest/docs/setup/additional-setup/cni/#helm-chart-parameters) An example is below:
 
-    ```yaml
-    apiVersion: install.istio.io/v1alpha1
-    kind: IstioOperator
-    spec:
-      components:
-        cni:
-          enabled: true
-          k8s:
-            overlays:
-            - apiVersion: "apps/v1"
-              kind: "DaemonSet"
-              name: "istio-cni-node"
-              patches:
-              - path: spec.template.spec.containers.[name:install-cni].securityContext.privileged
-                value: true
-      values:
-        cni:
-          image: rancher/mirrored-istio-install-cni:1.9.3
-          excludeNamespaces:
-            - istio-system
-            - kube-system
-          logLevel: info
-          cniBinDir: /opt/cni/bin
-          cniConfDir: /etc/cni/net.d
-    ```
+<Tabs>
+<TabItem value="RKE2">
+
+```yaml
+apiVersion: install.istio.io/v1alpha1
+kind: IstioOperator
+spec:
+  components:
+    cni:
+      enabled: true
+      k8s:
+        overlays:
+        - apiVersion: "apps/v1"
+          kind: "DaemonSet"
+          name: "istio-cni-node"
+          patches:
+          - path: spec.template.spec.containers.[name:install-cni].securityContext.privileged
+            value: true
+  values:
+    cni:
+      cniBinDir: /opt/cni/bin
+      cniConfDir: /etc/cni/net.d
+```
+</TabItem>
+<TabItem value="K3s">
+
+```yaml
+apiVersion: install.istio.io/v1alpha1
+kind: IstioOperator
+spec:
+  components:
+    cni:
+      enabled: true
+      k8s:
+        overlays:
+        - apiVersion: "apps/v1"
+          kind: "DaemonSet"
+          name: "istio-cni-node"
+          patches:
+          - path: spec.template.spec.containers.[name:install-cni].securityContext.privileged
+            value: true
+  values:
+    cni:
+      cniBinDir: /var/lib/rancher/k3s/data/current/bin
+      cniConfDir: /var/lib/rancher/k3s/agent/etc/cni/net.d
+```
+</TabItem>
+</Tabs>
 
 **Result:** Now you should be able to utilize Istio as desired, including sidecar injection and monitoring via Kiali.