Update missing log docs for .NET (#3561)

Co-authored-by: Fabrizio Ferri-Benedetti <[email protected]>
Co-authored-by: Phillip Carter <[email protected]>

content/en/docs/instrumentation/net/manual.md

@@ -393,7 +393,9 @@ available by
 
 ## Logs
 
-The logs API & SDK are currently under development.
+The documentation for the logs API and SDK is missing. You can help make it
+available by
+[editing this page](https://github.com/open-telemetry/opentelemetry.io/edit/main/content/en/docs/instrumentation/net/manual.md).
 
 ## Next steps