(docs) Update references to RenderNode

Author: toddrun

docs/api-reference/arcgis/deck-renderer.md

@@ -38,7 +38,9 @@ const renderer = new DeckRenderer(sceneView, {
   ]
 });
 
-sceneView.map.add(renderer);
+// DeckRenderer is a SceneView RenderNode. Constructing it attaches it to the
+// view; it should not be added to the map as a layer.
+renderer;
 ```
 
 
@@ -48,7 +50,7 @@ sceneView.map.add(renderer);
 new DeckRenderer(sceneView, props)
 ```
 
-- `sceneView` ([SceneView](https://developers.arcgis.com/javascript/latest/api-reference/esri-views-SceneView.html)) - the view to use this renderer with. `viewingMode` must be set to `'local'`.
+- `sceneView` ([SceneView](https://developers.arcgis.com/javascript/latest/api-reference/esri-views-SceneView.html)) - the view to use this renderer with. `viewingMode` must be set to `'local'`. `DeckRenderer` manages its internal deck.gl view state from the live `SceneView` camera and self-registers as a RenderNode; do not add it to `map.layers`.
 - `props` (object) - forwarded to a `Deck` instance. The following [Deck](../core/deck.md) props are supported:
 
 - `layers`

docs/api-reference/arcgis/overview.md

@@ -8,7 +8,7 @@ that acts as an interface between deck.gl and ArcGIS.
 
 2D integration with `MapView` is supported by the [DeckLayer](./deck-layer.md) class.
 
-3D integration with `SceneView` is experimental: see the [DeckRenderer](./deck-renderer.md) class.
+3D integration with `SceneView` is experimental and currently targets `viewingMode: 'local'`: see the [DeckRenderer](./deck-renderer.md) class.
 
 ## Installation
 

docs/developer-guide/base-maps/using-with-arcgis.md

@@ -10,4 +10,4 @@ Starting with v8.1, deck.gl has support for ArcGIS with the [@deck.gl/arcgis](..
 
 2D integration with `MapView` is supported by the [DeckLayer](../../api-reference/arcgis/deck-layer.md) class, see [pure JS example](https://github.com/visgl/deck.gl/tree/master/examples/get-started/pure-js/arcgis).
 
-3D integration with `SceneView` is experimental: see the [DeckRenderer](../../api-reference/arcgis/deck-renderer.md) class.
+3D integration with `SceneView` is experimental and currently targets `viewingMode: 'local'`; `DeckRenderer` attaches as a RenderNode rather than a map layer. See the [DeckRenderer](../../api-reference/arcgis/deck-renderer.md) class.