Add source node and target node to Cat Recovery

See elastic/elasticsearch#18187

Author: russcam

src/Nest/Cat/CatRecovery/CatRecoveryRecord.cs

@@ -23,9 +23,15 @@ public class CatRecoveryRecord : ICatRecord
 		[JsonProperty("source_host")]
 		public string SourceHost { get; set; }
 
+		[JsonProperty("source_node")]
+		public string SourceNode { get; set; }
+
 		[JsonProperty("target_host")]
 		public string TargetHost { get; set; }
 
+		[JsonProperty("target_node")]
+		public string TargetNode { get; set; }
+
 		[JsonProperty("repository")]
 		public string Repository { get; set; }