.NET: Convert legacy Pinpoint examples (#6380)

Author: rlhagerm

.doc_gen/metadata/pinpoint_metadata.yaml

@@ -4,6 +4,18 @@ pinpoint_SendMessages:
   synopsis: send email and text messages with &PIN;.
   category:
   languages:
+    .NET:
+      versions:
+        - sdk_version: 3
+          github: dotnetv3/Pinpoint
+          sdkguide:
+          excerpts:
+            - description: Send an email message.
+              snippet_tags:
+                - pinpoint.dotnet.pinpoint_send_email_message_api.complete
+            - description: Send an SMS message.
+              snippet_tags:
+                - pinpoint.dotnet.pinpoint_send_sms_message_api.complete
     Kotlin:
       versions:
         - sdk_version: 1

.dotnet/example_code_legacy/Pinpoint/pinpoint_send_email_message_api.cs

@@ -31,7 +31,7 @@ For prerequisites, see the [README](../README.md#Prerequisites) in the `dotnetv3
 
 ### Get started
 
-- [Hello CloudFormation](../CloudFormation/Actions/HelloCloudFormation.cs#L4) (`DescribeStackResources`)
+- [Hello CloudFormation](Actions/HelloCloudFormation.cs#L4) (`DescribeStackResources`)
 
 
 <!--custom.examples.start-->