fix #1127 missing lang property on metricaggregationbase, also noticed it was missing updatedesciptor

Author: Mpdreamz

src/Nest/DSL/Aggregations/MetricAggregationBaseDescriptor.cs

@@ -16,13 +16,18 @@ public interface IMetricAggregator
 
 		[JsonProperty("params")]
 		IDictionary<string, object> Params { get; set; }
+
+		[JsonProperty(PropertyName = "lang")]
+		string Language { get; set; }
+
 	}
 
 	public abstract class MetricAggregator : IMetricAggregator
 	{
 		public PropertyPathMarker Field { get; set; }
 		public string Script { get; set; }
 		public IDictionary<string, object> Params { get; set; }
+		public string Language { get; set; }
 	}
 
 	public abstract class MetricAggregationBaseDescriptor<TMetricAggregation, T> : IAggregationDescriptor, IMetricAggregator 
@@ -37,6 +42,8 @@ public abstract class MetricAggregationBaseDescriptor<TMetricAggregation, T> : I
 
 		IDictionary<string, object> IMetricAggregator.Params { get; set; }
 
+		string IMetricAggregator.Language { get; set; }
+
 		public TMetricAggregation Field(string field)
 		{
 			Self.Field = field;
@@ -60,5 +67,12 @@ public TMetricAggregation Params(Func<FluentDictionary<string, object>, FluentDi
 			Self.Params = paramSelector(new FluentDictionary<string, object>());
 			return (TMetricAggregation) this;
 		}
+
+		public TMetricAggregation Language(string language)
+		{
+			Self.Language = language;
+			return (TMetricAggregation)this;
+		}
+
 	}
 }

src/Nest/DSL/UpdateDescriptor.cs

@@ -130,6 +130,12 @@ public UpdateDescriptor<TDocument, TPartialDocument> Params(Func<FluentDictionar
 			return this;
 		}
 
+		public UpdateDescriptor<TDocument, TPartialDocument> Language(string language)
+		{
+			Self.Language = language;
+			return this;
+		}
+
 		public UpdateDescriptor<TDocument, TPartialDocument> Id(TDocument document, bool useAsUpsert)
 		{
 			((IDocumentOptionalPath<UpdateRequestParameters, TDocument>)Self).IdFrom = document;