Update links to packages moved to experimental (#2478)

Author: jessitron

doc/instrumentation-guide.md

@@ -5,7 +5,7 @@ A detailed explained guide how to instrument a package is available at [instrume
 For more comprehensive examples please refer to the [HTTP instrumentation][http-instrumentation] or [gRPC instrumentation][grpc-instrumentation] for node
 and [XMLHttpRequest instrumentation][xhr-instrumentation] for web.
 
-[base-instrumentation]: https://github.com/open-telemetry/opentelemetry-js/tree/main/packages/opentelemetry-instrumentation
-[http-instrumentation]: https://github.com/open-telemetry/opentelemetry-js/blob/main/packages/opentelemetry-instrumentation-http/src/http.ts#L59
-[grpc-instrumentation]: https://github.com/open-telemetry/opentelemetry-js/blob/main/packages/opentelemetry-instrumentation-grpc/src/instrumentation.ts#L28
-[xhr-instrumentation]: https://github.com/open-telemetry/opentelemetry-js/blob/main/packages/opentelemetry-instrumentation-xml-http-request/src/xhr.ts#L71
+[base-instrumentation]: https://github.com/open-telemetry/opentelemetry-js/tree/main/experimental/packages/opentelemetry-instrumentation
+[http-instrumentation]: https://github.com/open-telemetry/opentelemetry-js/blob/main/experimental/packages/opentelemetry-instrumentation-http/src/http.ts#L59
+[grpc-instrumentation]: https://github.com/open-telemetry/opentelemetry-js/blob/main/experimental/packages/opentelemetry-instrumentation-grpc/src/instrumentation.ts#L28
+[xhr-instrumentation]: https://github.com/open-telemetry/opentelemetry-js/blob/main/experimental/packages/opentelemetry-instrumentation-xml-http-request/src/xhr.ts#L71