mark LTREE as Preview (#20948)

Author: taroface

src/current/v25.4/cockroachdb-feature-availability.md

@@ -60,6 +60,10 @@ You can use the [Cloud API]({% link cockroachcloud/cloud-api.md %}#managed-backu
 **The following features are in preview** and are subject to change. To share feedback and/or issues, contact [Support](https://support.cockroachlabs.com/hc).
 {{site.data.alerts.end}}
 
+### `LTREE` data type
+
+The [`LTREE` data type]({% link {{ page.version.version }}/ltree.md %}) stores hierarchical tree-like structures. `LTREE` is useful for efficiently querying and managing hierarchical data without using recursive joins.
+
 ### Prometheus-compatible `metrics` endpoint
 
 [`http://<host>:<http-port>/metrics` Prometheus-compatible endpoint]({% link {{ page.version.version }}/prometheus-endpoint.md %}#metrics) is enhanced with additional static labels.

src/current/v25.4/ltree.md

@@ -5,6 +5,10 @@ toc: true
 docs_area: reference.sql
 ---
 
+{{site.data.alerts.callout_info}}
+{% include feature-phases/preview.md %}
+{{site.data.alerts.end}}
+
 The `LTREE` [data type]({% link {{ page.version.version }}/data-types.md %}) stores hierarchical tree-like structures as a *label path*, which is a sequence of dot-separated *labels*. Labels represent positions in a tree hierarchy. `LTREE` is useful for efficiently querying and managing hierarchical data without using recursive joins.
 
 ## Syntax