Fix syntax link on codex home page

see thread
https://elastic.slack.com/archives/C0JF80CJZ/p1775662761442549

Author: shainaraskas

src/Elastic.Codex/Landing/LandingView.cshtml

@@ -80,7 +80,7 @@
 				@GetIconSvg("plus", "w-4 h-4 fill-current")
 				Add your docs
 			</a>
-			<a href="https://docs-v3-preview.elastic.dev/elastic/docs-builder/tree/main/syntax"
+			<a href="https://elastic.github.io/docs-builder/syntax"
 			   target="_blank"
 			   rel="noopener"
 			   class="flex items-center gap-1.5 text-blue-elastic hover:underline">