DOCSP-49745: C# example for $geoNear (#12328) (#12350)

* DOCSP-49745: C# example for geoNear

* wip

* fix formatting

* MM small PR fixes

Author: rustagir

content/manual/manual/source/includes/driver-examples/aggregation/BuildersExamples.cs

@@ -154,7 +154,36 @@ public static void FacetStage()
             .Facet(bucketFacet, countFacet);
         // end facet
     }
- 
+  
+    public static void GeoNearStage()
+    {
+        // start geoNear
+        var pipeline = new EmptyPipelineDefinition<Theater>()
+            .GeoNear(
+                GeoJson.Point(GeoJson.Geographic(-74.1, 40.95)),
+                new GeoNearOptions<Theater, Theater>
+                {
+                  DistanceField = "distance",
+                  MaxDistance = 8000,
+                  Key = "location.geo",
+                  Query = Builders<Theater>.Filter.Eq(t => t.Location.Address.State, "NJ"),
+                });
+        // end geoNear
+    
+        // start geoNear min
+        var pipeline = new EmptyPipelineDefinition<Theater>()
+            .GeoNear(
+                GeoJson.Point(GeoJson.Geographic(-74.1, 40.95)),
+                new GeoNearOptions<Theater, Theater>
+                {
+                  DistanceField = "distance",
+                  MinDistance = 8000,
+                  Key = "location.geo",
+                  Query = Builders<Theater>.Filter.Eq(t => t.Location.Address.State, "NJ"),
+                })
+            .Limit(4);
+        // end geoNear min
+    }
     public static void GraphLookupStage()
     {
         // start graphLookupBasic

content/manual/manual/source/includes/driver-examples/aggregation/Theater.cs

@@ -0,0 +1,32 @@
+public class Theater
+{
+  public ObjectId Id { get; set; }
+
+  [BsonElement("theaterId")]
+  public int TheaterId { get; set; }
+
+  [BsonElement("location")]
+  public Location Location { get; set; }
+
+  [BsonElement("distance")]
+  public double? Distance { get; set; }
+}
+
+public class Location
+{
+  [BsonElement("address")]
+  public Address Address { get; set; }
+
+  [BsonElement("geo")]
+  public GeoJsonPoint<GeoJson2DGeographicCoordinates> Geo { get; set; }
+}
+
+[BsonIgnoreExtraElements]
+public class Address
+{
+  [BsonElement("city")]
+  public string City { get; set; }
+
+  [BsonElement("state")]
+  public string State { get; set; }
+}

content/manual/manual/source/includes/driver-examples/aggregation/sample-data-theaters.rst

@@ -0,0 +1,11 @@
+The C# examples on this page use the ``sample_mflix.theaters`` collection
+from the :atlas:`Atlas sample datasets </sample-data>`. To learn how to create a
+free MongoDB Atlas cluster and load the sample datasets, see
+:driver:`Get Started </csharp/current/quick-start/>` in the MongoDB .NET/C#
+Driver documentation.
+
+The following ``Theater``, ``Location``, and ``Address`` classes model
+the documents in the ``sample_mflix.theaters`` collection:
+
+.. literalinclude:: /includes/driver-examples/aggregation/Theater.cs
+   :language: csharp