fix: update terminology for allowed topic properties in PIP-447 documentation

Author: coderzc

pip/pip-447.md

@@ -94,23 +94,23 @@ Namespace-level configuration allows per-namespace control of which topic proper
 **CLI Examples:**
 
 ```bash
-# Set allowed properties
+# Set allowed properties keys
 pulsar-admin namespaces set-allowed-topic-properties-for-metrics \
-  --properties sla_tier,owner,environment \
+  --keys sla_tier,owner,environment \
   my-tenant/my-namespace
 
-# Get allowed properties
+# Get allowed properties keys
 pulsar-admin namespaces get-allowed-topic-properties-for-metrics my-tenant/my-namespace
 
-# Remove configuration
+# Remove allowed properties keys
 pulsar-admin namespaces remove-allowed-topic-properties-for-metrics my-tenant/my-namespace
 ```
 
 **Java Admin API:**
 
 ```java
 public interface Namespaces {
-    void setAllowedTopicPropertiesForMetrics(String namespace, Set<String> allowedProperties) throws PulsarAdminException;
+    void setAllowedTopicPropertiesForMetrics(String namespace, Set<String> allowedKeys) throws PulsarAdminException;
     Set<String> getAllowedTopicPropertiesForMetrics(String namespace) throws PulsarAdminException;
     void removeAllowedTopicPropertiesForMetrics(String namespace) throws PulsarAdminException;
 }