Update sidenav and add beta flag [netlify-build]

Author: pwseg

src/_data/sidenav/main.yml

@@ -406,6 +406,8 @@ sections:
       title: Generative Audiences
     - path: '/engage/audiences/organization'
       title: Organize Audiences
+    - path: '/engage/audiences/query-language'
+      title: Segment Query Language
 
   - section_title: Journeys
     description: "Learn how to create multi-step Journeys to tailor messages to your users."

src/engage/audiences/query-language.md

@@ -7,6 +7,9 @@ Segment's query language lets you define audience segments and computed traits.
 
 This reference provides a comprehensive overview of the Segment query language.
 
+> info "Segment's query language private beta"
+> Segment's query language is in private beta, and Segment is actively working on this feature. Some functionality may change before it becomes generally available.
+
 ## Overview
 
 Audience definitions specify the criteria for identifying users or accounts as members of a particular audience, while computed trait definitions outline the logic for aggregating or calculating values stored as traits on user or account level profiles.