Fix incorrect reference in documentation (#5571)

Author: stevejgordon

docs/client-concepts/high-level/serialization/custom-serialization.asciidoc

@@ -81,7 +81,7 @@ Hooking up the serializer is performed in the `ConnectionSettings` constructor
 var pool = new SingleNodeConnectionPool(new Uri("http://localhost:9200"));
 var connectionSettings = new ConnectionSettings(
     pool,
-    sourceSerializer: (builtin, settings) => new VanillaSerializer()); <1>
+    sourceSerializer: (builtin, settings) => new VanillaSerializer()); <1>
 var client = new ElasticClient(connectionSettings);
 ----
 <1> what the Func?
@@ -171,7 +171,7 @@ public class MyFirstCustomJsonNetSerializer : ConnectionSettingsAwareSerializerB
 }
 ----
 
-Using `MyCustomJsonNetSerializer`, we can serialize using
+Using `MyFirstCustomJsonNetSerializer`, we can serialize using
 
 * a Json.NET `NamingStrategy` that snake cases property names
 
@@ -211,7 +211,7 @@ Hooking up the serializer and using it is as follows
 var pool = new SingleNodeConnectionPool(new Uri("http://localhost:9200"));
 var connectionSettings = new ConnectionSettings(
     pool,
-    connection: new InMemoryConnection(), <1>
+    connection: new InMemoryConnection(), <1>
     sourceSerializer: (builtin, settings) => new MyFirstCustomJsonNetSerializer(builtin, settings))
     .DefaultIndex("my-index");
 
@@ -289,7 +289,7 @@ public class MySecondCustomJsonNetSerializer : ConnectionSettingsAwareSerializer
         };
 
     protected override ConnectionSettingsAwareContractResolver CreateContractResolver() =>
-        new MySecondCustomContractResolver(ConnectionSettings); <1>
+        new MySecondCustomContractResolver(ConnectionSettings); <1>
 }
 ----
 <1> override the contract resolver

src/Tests/Tests/ClientConcepts/HighLevel/Serialization/CustomSerialization.doc.cs

@@ -176,7 +176,7 @@ protected override void ModifyContractResolver(ConnectionSettingsAwareContractRe
 		}
 
 		/**
-		 * Using `MyCustomJsonNetSerializer`, we can serialize using
+		 * Using `MyFirstCustomJsonNetSerializer`, we can serialize using
 		 *
 		 * - a Json.NET `NamingStrategy` that snake cases property names
 		 * - `JsonSerializerSettings` that includes `null` properties