Make not-preferred logger naming consistent (#138210)

Author: nicktindall

server/src/main/java/org/elasticsearch/cluster/routing/allocation/allocator/BalancedShardsAllocator.java

@@ -77,7 +77,7 @@
 public class BalancedShardsAllocator implements ShardsAllocator {
 
     private static final Logger logger = LogManager.getLogger(BalancedShardsAllocator.class);
-    private static final Logger notPreferredLogger = LogManager.getLogger(BalancedShardsAllocator.class.getName() + ".not-preferred");
+    private static final Logger notPreferredLogger = LogManager.getLogger(BalancedShardsAllocator.class.getName() + ".not_preferred");
 
     public static final Setting<Float> SHARD_BALANCE_FACTOR_SETTING = Setting.floatSetting(
         "cluster.routing.allocation.balance.shard",

server/src/test/java/org/elasticsearch/cluster/routing/allocation/allocator/BalancedShardsAllocatorTests.java

@@ -1008,7 +1008,7 @@ public void testReturnEarlyOnShardAssignmentChanges() {
     }
 
     @TestLogging(
-        value = "org.elasticsearch.cluster.routing.allocation.allocator.BalancedShardsAllocator.not-preferred:DEBUG",
+        value = "org.elasticsearch.cluster.routing.allocation.allocator.BalancedShardsAllocator.not_preferred:DEBUG",
         reason = "debug logging for test"
     )
     public void testNotPreferredMovementIsLoggedAtDebugLevel() {
@@ -1031,7 +1031,7 @@ public Decision canRemain(
             }
         })), clusterState.getRoutingNodes().mutableCopy(), clusterState, ClusterInfo.EMPTY, SnapshotShardSizeInfo.EMPTY, 0L);
 
-        final var notPreferredLoggerName = BalancedShardsAllocator.class.getName() + ".not-preferred";
+        final var notPreferredLoggerName = BalancedShardsAllocator.class.getName() + ".not_preferred";
         MockLog.assertThatLogger(
             () -> balancedShardsAllocator.allocate(allocation),
             notPreferredLoggerName,