ES|QL: fix docs for functions in PREVIEW (elastic#123880)

Author: luigidellaquila

docs/reference/esql/functions/layout/categorize.asciidoc

@@ -953,7 +953,7 @@ protected static void renderDocs(String name) throws IOException {
         "// This is generated by ESQL's AbstractFunctionTestCase. Do no edit it. See ../README.md for how to regenerate it.\n\n";
 
     private static final String PREVIEW_CALLOUT =
-        "\npreview::[\"Do not use `VALUES` on production environments. This functionality is in technical preview and "
+        "\npreview::[\"Do not use on production environments. This functionality is in technical preview and "
             + "may be changed or removed in a future release. Elastic will work to fix any issues, but features in technical preview "
             + "are not subject to the support SLA of official GA features.\"]\n";