Properly drop preview status for WebSockets.next

(cherry picked from commit aa3e5c7)

Author: gsmet

docs/src/main/asciidoc/websockets-next-reference.adoc

@@ -5,7 +5,6 @@ https://github.com/quarkusio/quarkus/tree/main/docs/src/main/asciidoc
 ////
 [id="websockets-next-reference-guide"]
 = WebSockets Next reference guide
-:extension-status: preview
 include::_attributes.adoc[]
 :numbered:
 :sectnums:
@@ -14,8 +13,6 @@ include::_attributes.adoc[]
 :topics: web,websockets
 :extensions: io.quarkus:quarkus-websockets-next
 
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 The `quarkus-websockets-next` extension provides a modern declarative API to define WebSocket server and client endpoints.
 
 == The WebSocket protocol

docs/src/main/asciidoc/websockets-next-tutorial.adoc

@@ -14,9 +14,6 @@ include::_attributes.adoc[]
 This guide explains how your Quarkus application can utilize web sockets to create interactive web applications.
 In this guide, we will develop a very simple chat application using web sockets to receive and send messages to the other connected users.
 
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 == Prerequisites
 
 include::{includes}/prerequisites.adoc[]