namespacesRegexdocs: Fix `namespaceRegexes` in full-cluster-secret-store.yaml (#3681)

This fixes a typo on https://external-secrets.io/v0.9.20/api/clustersecretstore/, in which the property is incorrectly called `namespacesRegex`

Signed-off-by: Arthur Kepler <610274+excalq@users.noreply.github.com>

docs/snippets/full-cluster-secret-store.yaml

@@ -151,8 +151,8 @@ spec:
         - "namespace-a"
         - "namespace-b"
 
-    # Namespace regex is helpful for namespace naming convention or when an external tool auto generate namespaces with prefix
-    - namespacesRegex:
+    # Namespace regexes are useful for policy management or when external tools auto-generate namespaces with prefixes/suffixes
+    - namespaceRegexes:
         - "namespace-a-.*" # All namespaces prefixed by namespace-a- will work
         - "namespace-b-.*" # All namespaces prefixed by namespace-b- will work