docs/sdks/s3/go: fixup the examples and ensure they all compile

Closes TIG-3469

This moves the example files into a separate folder so that we can
use editor tooling to ensure that they not only compile, but we have
tab-completion.

This will be done to the other languages when I continue plowing
through the examples.

All examples are known to work and have been tested locally.

Author: Xe

docs/buckets/object-notifications.md

@@ -141,5 +141,5 @@ single region then collates those events and sends them to the webhook. The
 
 ## Next steps
 
-- Check out the [Example Webhook](/docs/sdks/s3/aws-go-sdk.md#webhook) for more
+- Check out the [Example Webhook](/docs/sdks/s3/aws-go-sdk.mdx#webhook) for more
   details on how to use them in your application.

docs/objects/query-metadata.md

@@ -63,5 +63,5 @@ Example queries that can be performed:
 
 ## Next steps
 
-- Check out the [Example usage](/docs/sdks/s3/aws-go-sdk.md#metadata-querying)
-  for more details on how to use them in your application.
+- Check out the [Example usage](/docs/sdks/s3/aws-go-sdk#metadata-querying) for
+  more details on how to use them in your application.