Add score to TermVectorTerm (#3606)

Closes #3604

(cherry picked from commit 3853ed4)

Author: russcam

src/Nest/Document/Single/TermVectors/TermVectorTerm.cs

@@ -12,6 +12,9 @@ public class TermVectorTerm
 		[DataMember(Name ="term_freq")]
 		public int TermFrequency { get; internal set; }
 
+		[DataMember(Name = "score")]
+		public double Score { get; internal set; }
+
 		[DataMember(Name ="tokens")]
 		public IReadOnlyCollection<Token> Tokens { get; internal set; } =
 			EmptyReadOnly<Token>.Collection;

src/Tests/Tests/Document/Multiple/MultiTermVectors/MultiTermVectorsApiTests.cs

@@ -119,6 +119,7 @@ private static void AssertTermVectors(TermVector vectors)
 				vectorTerm.Value.DocumentFrequency.Should().BeGreaterThan(0);
 				vectorTerm.Value.TotalTermFrequency.Should().BeGreaterThan(0);
 				vectorTerm.Value.Tokens.Should().NotBeEmpty();
+				vectorTerm.Value.Score.Should().BeGreaterThan(0);
 
 				var token = vectorTerm.Value.Tokens.First();
 				token.EndOffset.Should().BeGreaterThan(0);
@@ -202,6 +203,7 @@ private static void AssertTermVectors(TermVector vectors)
 				vectorTerm.Value.TermFrequency.Should().BeGreaterThan(0);
 				vectorTerm.Value.TotalTermFrequency.Should().BeGreaterThan(0);
 				vectorTerm.Value.Tokens.Should().NotBeEmpty();
+				vectorTerm.Value.Score.Should().BeGreaterThan(0);
 
 				var token = vectorTerm.Value.Tokens.First();
 				token.EndOffset.Should().BeGreaterThan(0);

src/Tests/Tests/Document/Single/TermVectors/TermVectorsApiTests.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Linq;
 using Elasticsearch.Net;
 using FluentAssertions;
 using Nest;
@@ -110,6 +111,7 @@ private static void AssertTermVector(TermVector termvector)
 			termvector.FieldStatistics.SumOfDocumentFrequencies.Should().BeGreaterThan(0);
 			termvector.FieldStatistics.SumOfTotalTermFrequencies.Should().BeGreaterThan(0);
 			termvector.Terms.Should().NotBeNull();
+			termvector.Terms.First().Value.Score.Should().BeGreaterThan(0);
 		}
 	}
 }