[charts-premium] Mark Heamp WebGL render as stable

Author: alexfauquette

docs/data/charts/heatmap/heatmap.md

@@ -116,12 +116,7 @@ Use the `cell` slot to replace the default cell shape or add labels.
 
 {{"demo": "CustomItem.js"}}
 
-## WebGL renderer [<span class="plan-premium"></span>](/x/introduction/licensing/#premium-plan 'Premium plan') 🧪
-
-:::warning
-This feature is in preview.
-It is ready for production use, but its API, visuals and behavior may change in future minor or patch releases.
-:::
+## WebGL renderer [<span class="plan-premium"></span>](/x/introduction/licensing/#premium-plan 'Premium plan')
 
 Heatmaps can have many cells, which can slow down rendering.
 Set the `renderer` prop to `'webgl'` for better performance with large datasets.