Transformations: Move regression analysis transformation to private preview (#79500)

* move regression analysis transformation to private preview

* fix case

docs/sources/panels-visualizations/query-transform-data/transform-data/index.md

@@ -39,7 +39,7 @@ labels:
     - enterprise
     - oss
 title: Transform data
-description: Use transformations to rename fields, join series data, apply mathematical operations, and more
+description: Use transformations to manipulate your data before visualizations are applied
 weight: 100
 ---
 
@@ -1278,7 +1278,7 @@ There are two different models:
 - **Polynomial regression** - Fits a polynomial function to the data.
   {{< figure src="/static/img/docs/transformations/polynomial-regression.png" class="docs-image--no-shadow" max-width= "1100px" alt="A time series visualization with a curved line representing the polynomial function" >}}
 
-> **Note:** This transformation is an experimental feature. Engineering and on-call support is not available. Documentation is either limited or not provided outside of code comments. No SLA is provided. Enable the `regressionTransformation` feature toggle in Grafana to use this feature. Contact Grafana Support to enable this feature in Grafana Cloud.
+> **Note:** This transformation is currently in private preview. Grafana Labs offers support on a best-effort basis, and breaking changes might occur prior to the feature being made generally available.
 
 {{% docs/reference %}}
 [Table panel]: "/docs/grafana/ -> /docs/grafana/<GRAFANA VERSION>/panels-visualizations/visualizations/table"