Remove Neighbors and use Union<Distance,int> for Precision (#4107)

Relates: #4091

This commit removes the Neighbors property from Completion field data type mapping and updates the Precision type to a Union<Distance,int>, to match the context suggest query inputs.

Author: russcam

src/Nest/Search/Suggesters/ContextSuggester/CategorySuggestContext.cs renamed to src/Nest/Mapping/Types/Specialized/Completion/CategorySuggestContext.cs

@@ -0,0 +1,33 @@
+using System.Runtime.Serialization;
+using Elasticsearch.Net.Utf8Json;
+
+namespace Nest
+{
+	[InterfaceDataContract]
+	public interface IGeoSuggestContext : ISuggestContext
+	{
+		[DataMember(Name = "precision")]
+		Union<Distance, int> Precision { get; set; }
+	}
+
+	[DataContract]
+	public class GeoSuggestContext : SuggestContextBase, IGeoSuggestContext
+	{
+		public Union<Distance, int> Precision { get; set; }
+		public override string Type => "geo";
+	}
+
+	[DataContract]
+	public class GeoSuggestContextDescriptor<T>
+		: SuggestContextDescriptorBase<GeoSuggestContextDescriptor<T>, IGeoSuggestContext, T>, IGeoSuggestContext
+		where T : class
+	{
+		protected override string Type => "geo";
+
+		Union<Distance, int> IGeoSuggestContext.Precision { get; set; }
+
+		public GeoSuggestContextDescriptor<T> Precision(Distance precision) => Assign(precision, (a, v) => a.Precision = v);
+
+		public GeoSuggestContextDescriptor<T> Precision(int? precision) => Assign(precision, (a, v) => a.Precision = v);
+	}
+}

src/Nest/Mapping/Types/Specialized/Completion/GeoSuggestContext.cs

@@ -2,7 +2,6 @@
 using Elasticsearch.Net.Utf8Json;
 using Elasticsearch.Net.Utf8Json.Internal;
 
-
 namespace Nest
 {
 	internal class SuggestContextFormatter : IJsonFormatter<ISuggestContext>

src/Nest/Search/Suggesters/ContextSuggester/ISuggestContext.cs renamed to src/Nest/Mapping/Types/Specialized/Completion/ISuggestContext.cs

@@ -347,6 +347,10 @@ public static PropertiesDescriptor<TProject> ProjectProperties<TProject>(Propert
 						.Category(c => c
 							.Name("color")
 						)
+						.GeoLocation(c => c
+							.Name("geo")
+							.Precision(1)
+						)
 					)
 				)
 				.Scalar(p => p.NumberOfCommits, n => n.Store())