Add token_limit and force_unigrams to phrase suggest (#3112)

Closes #3109

Author: russcam

src/Nest/Search/Suggesters/PhraseSuggester/PhraseSuggester.cs

@@ -41,6 +41,12 @@ public interface IPhraseSuggester : ISuggester
 
 		[JsonProperty("smoothing")]
 		SmoothingModelContainer Smoothing { get; set; }
+
+		[JsonProperty("token_limit")]
+		int? TokenLimit { get; set; }
+
+		[JsonProperty("force_unigrams")]
+		bool? ForceUnigrams { get; set; }
 	}
 
 	public class PhraseSuggester : SuggesterBase, IPhraseSuggester
@@ -56,6 +62,8 @@ public class PhraseSuggester : SuggesterBase, IPhraseSuggester
 		public IPhraseSuggestHighlight Highlight { get; set; }
 		public IPhraseSuggestCollate Collate { get; set; }
 		public SmoothingModelContainer Smoothing { get; set; }
+		public int? TokenLimit { get; set; }
+		public bool? ForceUnigrams { get; set; }
 	}
 
 	public class PhraseSuggesterDescriptor<T> : SuggestDescriptorBase<PhraseSuggesterDescriptor<T>, IPhraseSuggester, T>, IPhraseSuggester
@@ -72,6 +80,8 @@ public class PhraseSuggesterDescriptor<T> : SuggestDescriptorBase<PhraseSuggeste
 		IPhraseSuggestHighlight IPhraseSuggester.Highlight { get; set; }
 		IPhraseSuggestCollate IPhraseSuggester.Collate { get; set; }
 		SmoothingModelContainer IPhraseSuggester.Smoothing { get; set; }
+		int? IPhraseSuggester.TokenLimit { get; set; }
+		bool? IPhraseSuggester.ForceUnigrams { get; set; }
 
 		public PhraseSuggesterDescriptor<T> Text(string text) => Assign(a => a.Text = text);
 
@@ -99,5 +109,9 @@ public PhraseSuggesterDescriptor<T> Collate(Func<PhraseSuggestCollateDescriptor<
 
 		public PhraseSuggesterDescriptor<T> Smoothing(Func<SmoothingModelContainerDescriptor, SmoothingModelContainer> selector) =>
 			Assign(a => a.Smoothing = selector?.Invoke(new SmoothingModelContainerDescriptor()));
+
+		public PhraseSuggesterDescriptor<T> TokenLimit(int? tokenLimit) => Assign(a => a.TokenLimit = tokenLimit);
+
+		public PhraseSuggesterDescriptor<T> ForceUnigrams(bool? forceUnigrams = true) => Assign(a => a.ForceUnigrams = forceUnigrams);
 	}
 }

src/Tests/Search/Request/SuggestUsageTests.cs

@@ -61,7 +61,9 @@ public SuggestUsageTests(ReadOnlyCluster cluster, EndpointUsage usage) : base(cl
 						},
 						field = "name",
 						gram_size = 1,
-						real_word_error_likelihood = 0.5
+						real_word_error_likelihood = 0.5,
+						token_limit = 5,
+						force_unigrams = false
 					  },
 					  text = "hello world"
 					} },
@@ -134,6 +136,8 @@ public SuggestUsageTests(ReadOnlyCluster cluster, EndpointUsage usage) : base(cl
 					.Field(p => p.Name)
 					.Text("hello world")
 					.RealWordErrorLikelihood(0.5)
+					.TokenLimit(5)
+					.ForceUnigrams(false)
 				)
 			);
 
@@ -206,7 +210,9 @@ public SuggestUsageTests(ReadOnlyCluster cluster, EndpointUsage usage) : base(cl
 							},
 							GramSize = 1,
 							Field = "name",
-							RealWordErrorLikelihood = 0.5
+							RealWordErrorLikelihood = 0.5,
+							TokenLimit = 5,
+							ForceUnigrams = false
 						}
 					} },
 				}