Fix: Better error when no constructor found

Author: alkampfergit

src/MongoDB.Bson/Serialization/Serializers/BsonClassMapSerializer.cs

@@ -414,7 +414,7 @@ private BsonCreatorMap ChooseBestCreator(Dictionary<string, object> values)
 
             if (creatorMap == null)
             {
-                throw new BsonSerializationException("No matching creator found.");
+                throw new BsonSerializationException($"No matching creator found for class {_classMap.ClassType.FullName}.");
             }
 
             return creatorMap;