Change deprecation message for API parameter value 'master_node' of parameter 'metric' (#2880)

Signed-off-by: Tianli Feng <ftianli@amazon.com>

rest-api-spec/src/main/resources/rest-api-spec/test/cluster.state/20_filtering.yml

@@ -169,7 +169,7 @@ setup:
       cluster.state:
         metric: [ master_node, version ]
       allowed_warnings:
-        - 'Parameter [master_timeout] is deprecated and will be removed in 3.0. To support inclusive language, please use [cluster_manager_timeout] instead.'
+        - 'Assigning [master_node] to parameter [metric] is deprecated and will be removed in 3.0. To support inclusive language, please use [cluster_manager_node] instead.'
 
   - match: { cluster_uuid: $cluster_uuid }
   - is_true: master_node

server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterRerouteAction.java

@@ -83,7 +83,7 @@ public class RestClusterRerouteAction extends BaseRestHandler {
     // It's used to log deprecation when request parameter 'metric' contains 'master_node', or request parameter 'master_timeout' is used.
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestClusterRerouteAction.class);
     private static final String DEPRECATED_MESSAGE_MASTER_NODE =
-        "Deprecated value [master_node] used for parameter [metric]. To promote inclusive language, please use [cluster_manager_node] instead. It will be unsupported in a future major version.";
+        "Assigning [master_node] to parameter [metric] is deprecated and will be removed in 3.0. To support inclusive language, please use [cluster_manager_node] instead.";
 
     @Override
     public List<Route> routes() {

server/src/main/java/org/opensearch/rest/action/admin/cluster/RestClusterStateAction.java

@@ -76,7 +76,7 @@ public class RestClusterStateAction extends BaseRestHandler {
     // It's used to log deprecation when request parameter 'metric' contains 'master_node', or request parameter 'master_timeout' is used.
     private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(RestClusterStateAction.class);
     private static final String DEPRECATED_MESSAGE_MASTER_NODE =
-        "Deprecated value [master_node] used for parameter [metric]. To promote inclusive language, please use [cluster_manager_node] instead. It will be unsupported in a future major version.";
+        "Assigning [master_node] to parameter [metric] is deprecated and will be removed in 3.0. To support inclusive language, please use [cluster_manager_node] instead.";
 
     @Override
     public String getName() {