Add US2-FED (gov2) region to LaunchDarkly integration docs

Add gov2 to the comma-separated region list in the site-region
shortcode block in the LaunchDarkly README. US2-FED is a new Datadog
GovCloud data center (IL5).

Related: DataDog/documentation#36153 (DOCS-14086)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: hestonhoffman

launchdarkly/README.md

@@ -3,7 +3,7 @@
 ## Overview
 
 <!-- partial
-{{% site-region region="gov" %}}
+{{% site-region region="gov,gov2" %}}
 **The LaunchDarkly integration is not supported for the Datadog {{< region-param key="dd_site_name" >}} site**.
 {{% /site-region %}}
 partial -->