Update sampling documentation's FAQ to mention telemetry initializers available in all SDKs

The current documentation wording does not clarify that telemetry initializers are available in all SDKs, and the only example is for the ASP.NET SDK. This PR clarifies that multiple SDKs support this feature.

Author: johndowns

articles/azure-monitor/app/sampling.md

@@ -7,7 +7,7 @@ ms.topic: conceptual
 author: mrbullwinkle
 ms.author: mbullwin
 ms.date: 03/14/2019
-
+ms.custom: fasttrack-edit
 ms.reviewer: vitalyg
 ---
 
@@ -535,7 +535,7 @@ apply sampling to those items already sampled in the SDK itself.'
 
 *There are certain rare events I always want to see. How can I get them past the sampling module?*
 
-* The best way to achieve this is to write a custom [TelemetryInitializer](../../azure-monitor/app/api-filtering-sampling.md#addmodify-properties-itelemetryinitializer), which sets the `SamplingPercentage` to 100 on the telemetry item you want retained, as shown below. As initializers are guaranteed to be run before telemetry processors (including sampling), this ensures that all sampling techniques will ignore this item from any sampling considerations.
+* The best way to achieve this is to write a custom [TelemetryInitializer](../../azure-monitor/app/api-filtering-sampling.md#addmodify-properties-itelemetryinitializer), which sets the `SamplingPercentage` to 100 on the telemetry item you want retained, as shown below. As initializers are guaranteed to be run before telemetry processors (including sampling), this ensures that all sampling techniques will ignore this item from any sampling considerations. Custom telemetry initializers are available in the ASP.NET SDK, the ASP.NET Core SDK, the JavaScript SDK, and the Java SDK. For example, you can configure a telemetry initializer using the ASP.NET SDK:
 
 ```csharp
      public class MyTelemetryInitializer : ITelemetryInitializer