added url to github for filer processor in drop spans

content/en/ninja-workshops/10-advanced-otel/5-dropping-spans/_index.md

@@ -5,7 +5,7 @@ time: 10 minutes
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-In this section, we will explore how to use the **Filter Processor** to selectively drop spans based on certain conditions.
+In this section, we will explore how to use the [**Filter Processor**](https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/processor/filterprocessor/README.md) to selectively drop spans based on certain conditions.
 
 Specifically, we will drop traces based on the span name, which is commonly used to filter out unwanted spans such as health checks or internal communication traces. In this case, we will be filtering out spans whose name is `"/_healthz"`, typically associated with health check requests and usually are quite "**noisy**".