fix: Updated docs about using a slash in ignoreDifferences (#15144)

Signed-off-by: Christian Hernandez <[email protected]>

docs/user-guide/diffing.md

@@ -68,6 +68,15 @@ spec:
 
 The above configuration will ignore differences from all fields owned by `kube-controller-manager` for all resources belonging to this application.
 
+If you have a slash `/` in your pointer path, you can use the `~1` character. For example:
+
+```yaml
+spec:
+  ignoreDifferences:
+  - kind: Node
+    jsonPointers: /metadata/labels/node-role.kubernetes.io~1worker
+```
+
 ## System-Level Configuration
 
 The comparison of resources with well-known issues can be customized at a system level. Ignored differences can be configured for a specified group and kind