fix: invalid yaml in example

Author: jdockerty

docs/book/src/topics/multitenancy.md

@@ -56,7 +56,7 @@ kind: AWSClusterControllerIdentity
 metadata:
   name: "default"
 spec:
-  allowedNamespaces:{}  # matches all namespaces
+  allowedNamespaces: {}  # matches all namespaces
 ```
 `AWSClusterControllerIdentity` is immutable to avoid any unwanted overrides to the allowed namespaces, especially during upgrading clusters.
 
@@ -231,7 +231,7 @@ kind: AWSClusterControllerIdentity
 metadata:
   name: "default"
 spec:
-  allowedNamespaces:{}  # matches all namespaces
+  allowedNamespaces: {}  # matches all namespaces
 ```
 
 ```yaml